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FETCHMAIL(1)		  fetchmail reference manual		  FETCHMAIL(1)

NAME
       fetchmail - fetch mail from a POP, IMAP,	ETRN, or ODMR-capable server

SYNOPSIS
       fetchmail [option...] [mailserver...]
       fetchmailconf

DESCRIPTION
       fetchmail  is  a	mail-retrieval and forwarding utility; it fetches mail
       from remote mail	servers	and forwards it	to  your  local	 (client)  ma-
       chine's	delivery system.  You can then handle the retrieved mail using
       normal mail user	agents such as mutt(1),	elm(1) or Mail(1).  The	fetch-
       mail utility can	be run in a daemon mode	to repeatedly poll one or more
       systems at a specified interval.

       The fetchmail program can gather	mail from servers  supporting  any  of
       the  common  mail-retrieval protocols: POP2 (legacy, to be removed from
       future release),	POP3, IMAP2bis,	IMAP4, and IMAP4rev1.  It can also use
       the ESMTP ETRN extension	and ODMR.  (The	RFCs describing	all these pro-
       tocols are listed at the	end of this manual page.)

       While fetchmail is primarily intended to	be used	over on-demand	TCP/IP
       links  (such  as	 SLIP  or PPP connections), it may also	be useful as a
       message transfer	agent for sites	which refuse for security  reasons  to
       permit (sender-initiated) SMTP transactions with	sendmail.

SUPPORT, TROUBLESHOOTING
       For troubleshooting, tracing and	debugging, you need to increase	fetch-
       mail's  verbosity  to actually see what happens.	To do that, please run
       both of the two following commands, adding all  of  the	options	 you'd
       normally	use.

	      env LC_ALL=C fetchmail -V	-v --nodetach --nosyslog

	      (This  command  line prints in English how fetchmail understands
	      your configuration.)

	      env LC_ALL=C fetchmail -vvv  --nodetach --nosyslog

	      (This command line actually runs fetchmail with verbose  English
	      output.)

       Also	  see	    item       #G3	 in	  fetchmail's	   FAQ
       <https://fetchmail.sourceforge.io/fetchmail-FAQ.html#G3>.

       You can omit the	LC_ALL=C part above if you want	output	in  the	 local
       language	 (if  supported). However if you are posting to	mailing	lists,
       please leave it in. The maintainers do not necessarily understand  your
       language, please	use English.

TLS (SSL) QUICKSTART
       Your  fetchmail	distribution  should have come with a README.SSL file,
       which see.  It is recommended to	configure all polls with --ssl	--ssl-
       proto  tls1.2+  if  supported by	the server, which configures fetchmail
       along recent  IETF  proposed  standards	and  best  current  practices,
       RFC-8314, RFC-8996, RFC-8997.

CONCEPTS
       If fetchmail is used with a POP or an IMAP server (but not with ETRN or
       ODMR),  it has two fundamental modes of operation for each user account
       from which it retrieves mail: singledrop- and multidrop-mode.

       In singledrop-mode,
	      fetchmail	assumes	that all messages in the user's	account	(mail-
	      box) are intended	for a single recipient.	 The identity  of  the
	      recipient	 will  either default to the local user	currently exe-
	      cuting fetchmail,	or will	need to	be explicitly specified	in the
	      configuration file.

	      fetchmail	uses singledrop-mode when the  fetchmailrc  configura-
	      tion  contains  at  most a single	local user specification for a
	      given server account.

       In multidrop-mode,
	      fetchmail	assumes	that the mail server account actually contains
	      mail intended for	any number of  different  recipients.	There-
	      fore,  fetchmail must attempt to deduce the proper "envelope re-
	      cipient" from the	mail headers of	each message.  In this mode of
	      operation, fetchmail almost  resembles  a	 mail  transfer	 agent
	      (MTA).

	      Note  that  neither the POP nor IMAP protocols were intended for
	      use in this fashion, and hence envelope information is often not
	      directly available. The ISP must store the envelope  information
	      in  some message header and. The ISP must	also store one copy of
	      the message per recipient. If either of the  conditions  is  not
	      fulfilled,  this	process	 is unreliable,	because	fetchmail must
	      then resort to guessing the true envelope	recipient(s) of	a mes-
	      sage. This usually fails for mailing  list  messages  and	 Bcc:d
	      mail, or mail for	multiple recipients in your domain.

	      fetchmail	 uses  multidrop-mode  when  more  than	one local user
	      and/or a wildcard	is specified for a particular  server  account
	      in the configuration file.

       In ETRN and ODMR	modes,
	      these  considerations do not apply, as these protocols are based
	      on SMTP, which provides explicit envelope	recipient information.
	      These protocols always support multiple recipients.

       As each message is retrieved, fetchmail normally	delivers it  via  SMTP
       to  port	25 on the machine it is	running	on (localhost),	just as	though
       it were being passed in over a normal TCP/IP link.  fetchmail  provides
       the  SMTP  server  with an envelope recipient derived in	the manner de-
       scribed previously.  The	mail will then be delivered according to  your
       MTA's  rules  (the Mail Transfer	Agent is usually sendmail(8), exim(8),
       or postfix(8)).	Invoking your system's MDA (Mail  Delivery  Agent)  is
       the  duty  of  your  MTA.  All the delivery-control mechanisms (such as
       .forward	files) normally	available through your system  MTA  and	 local
       delivery	agents will therefore be applied as usual.

       If  your	 fetchmail  configuration  sets	a local	MDA (see the --mda op-
       tion), it will be used directly instead of talking SMTP to port 25.

       If the program fetchmailconf is available, it will assist you  in  set-
       ting  up	 and editing a fetchmailrc configuration.  It runs under the X
       window system and requires that the language Python and the Tk  toolkit
       (with  Python  bindings)	 be  present on	your system.  If you are first
       setting up fetchmail for	single-user mode, it is	recommended  that  you
       use  Novice  mode.   Expert mode	provides complete control of fetchmail
       configuration, including	the multidrop features.	 In either  case,  the
       'Autoprobe' button will tell you	the most capable protocol a given mail
       server supports,	and warn you of	potential problems with	that server.

PREFACE	ON THIS	MANUAL
       Fetchmail's  run-time  strings have been	translated (localized) to some
       languages, but the manual is only available in English.	In some	situa-
       tions, for comparing output to manual, it  may  be  helpful  to	switch
       fetchmail to English output by overriding the locale variables, for in-
       stance:

	      env LC_ALL=C fetchmail # add other options before	the hash

	      env LANG=en fetchmail # other options before the hash

       or similar. Details vary	by operating system.

GENERAL	OPERATION
       The  behavior  of fetchmail is controlled by command-line options and a
       run control file, ~/.fetchmailrc, the syntax of which we	describe in  a
       later  section  (this  file  is	what the fetchmailconf program edits).
       Command-line options override ~/.fetchmailrc declarations.

       Each server name	that you specify following the options on the  command
       line will be queried.  If you do	not specify any	servers	on the command
       line,  each  'poll'  entry in your ~/.fetchmailrc file will be queried,
       unless the idle option is used, which see.

       To facilitate the use of	fetchmail in scripts and pipelines, it returns
       an appropriate exit code	upon termination -- see	EXIT CODES below.

       The following options modify the	behavior of fetchmail.	It  is	seldom
       necessary  to specify any of these once you have	a working .fetchmailrc
       file set	up.

       Almost all options have a corresponding keyword which can  be  used  to
       declare them in a .fetchmailrc file.

       Some  special  options are not covered here, but	are documented instead
       in sections on AUTHENTICATION and DAEMON	MODE which follow.

   General Options
       -? | --help
	      Displays option help.

       -V | --version
	      Displays the version information for your	copy of	fetchmail.  No
	      mail fetch is performed.	Instead, for  each  server  specified,
	      all  the	option information that	would be computed if fetchmail
	      were connecting to that server is	displayed.  Any	 non-printable
	      characters in passwords or other string names are	shown as back-
	      slashed C-like escape sequences.	This option is useful for ver-
	      ifying that your options are set the way you want	them.

       -c | --check
	      Return  a	status code to indicate	whether	there is mail waiting,
	      without actually fetching	or deleting mail (see EXIT  CODES  be-
	      low).   This  option turns off daemon mode (in which it would be
	      useless).	 It does not play well with queries to multiple	sites,
	      and does not work	with ETRN or ODMR.  It	will  return  a	 false
	      positive	if  you	 leave	read but undeleted mail	in your	server
	      mailbox and your fetch protocol cannot tell kept	messages  from
	      new  ones.   This	 means	it  will work with IMAP, not work with
	      POP2, and	may occasionally flake out under POP3.

       -s | --silent
	      Silent mode.  Suppresses all progress/status messages  that  are
	      normally	echoed to standard output during a fetch (but does not
	      suppress actual error messages).	The --verbose option overrides
	      this.

       -v | --verbose
	      Verbose mode.  All control messages passed between fetchmail and
	      the mail server are echoed to stdout.  Overrides --silent.  Dou-
	      bling this option	(-v -v)	causes extra diagnostic	information to
	      be printed.

       --nosoftbounce
	      (since v6.3.10, Keyword: set no softbounce, since	v6.3.10)
	      Hard bounce mode.	All permanent delivery errors  cause  messages
	      to  be deleted from the upstream server, see "no softbounce" be-
	      low.

       --softbounce
	      (since v6.3.10, Keyword: set softbounce, since v6.3.10)
	      Soft bounce mode.	All permanent delivery errors  cause  messages
	      to be left on the	upstream server	if the protocol	supports that.
	      This  option  is on by default to	match historic fetchmail docu-
	      mentation, and will be changed to	hard bounce mode in  the  next
	      fetchmail	release.

   Disposal Options
       -a | --all | (since v6.3.3) --fetchall
	      (Keyword:	fetchall, since	v3.0)
	      Retrieve	both old (seen)	and new	messages from the mail server.
	      The default is to	fetch only messages the	server has not	marked
	      seen.   Under  POP3,  this  option  also	forces the use of RETR
	      rather than TOP.	Note that POP2	retrieval  behaves  as	though
	      --all  is	always on (see RETRIEVAL FAILURE MODES below) and this
	      option does not work with	ETRN or	ODMR.  While the -a and	 --all
	      command-line and fetchall	rcfile options have been supported for
	      a	 long  time,  the  --fetchall command-line option was added in
	      v6.3.3.

       -k | --keep
	      (Keyword:	keep)
	      Keep retrieved messages on the remote  mail  server.   Normally,
	      messages	are  deleted  from the folder on the mail server after
	      they have	been retrieved.	 Specifying the	keep option causes re-
	      trieved messages to remain in your folder	on  the	 mail  server.
	      This  option does	not work with ETRN or ODMR. If used with POP3,
	      it is recommended	to also	specify	the --uidl option or uidl key-
	      word.

       -K | --nokeep
	      (Keyword:	nokeep)
	      Delete retrieved messages	from the remote	mail server.  This op-
	      tion forces retrieved mail to be deleted.	 It may	be  useful  if
	      you have specified a default of keep in your .fetchmailrc.  This
	      option is	forced on with ETRN and	ODMR.

       -F | --flush
	      (Keyword:	flush)
	      POP3/IMAP	 only.	 This is a dangerous option and	can cause mail
	      loss when	used improperly. It deletes old	(seen)	messages  from
	      the  mail	 server	before retrieving new messages.	 Warning: This
	      can cause	mail loss if you check your mail  with	other  clients
	      than  fetchmail,	and cause fetchmail to delete a	message	it had
	      never fetched before.  It	can also cause mail loss if  the  mail
	      server  marks  the message seen after retrieval (IMAP2 servers).
	      You should probably not use this option  in  your	 configuration
	      file.  If	 you use it with POP3, you must	use the	'uidl' option.
	      What you probably	want is	the default setting:  if  you  do  not
	      specify  '-k', then fetchmail will automatically delete messages
	      after successful delivery.

       --limitflush
	      POP3/IMAP	only, since version 6.3.0.  Delete oversized  messages
	      from  the	 mail  server before retrieving	new messages. The size
	      limit should be separately specified with	 the  --limit  option.
	      This option does not work	with ETRN or ODMR.

   Protocol and	Query Options
       -p <proto> | --proto <proto> | --protocol <proto>
	      (Keyword:	proto[col])
	      Specify  the  protocol to	use when communicating with the	remote
	      mail server.  If no protocol is specified, the default is	 AUTO.
	      proto may	be one of the following:

	      AUTO   Tries  IMAP,  POP3,  and  POP2 (skipping any of these for
		     which support has not been	compiled in).

	      POP2   Post Office Protocol 2 (legacy, to	be removed from	future
		     release)

	      POP3   Post Office Protocol 3

	      APOP   Use POP3 with old-fashioned MD5-challenge authentication.
		     Considered	not resistant to man-in-the-middle attacks.

	      RPOP   Use POP3 with RPOP	authentication.

	      KPOP   Use POP3 with Kerberos V4 authentication on port 1109.

	      SDPS   Use POP3 with Demon Internet's SDPS extensions.

	      IMAP   IMAP2bis, IMAP4, or  IMAP4rev1  (fetchmail	 automatically
		     detects their capabilities).

	      ETRN   Use the ESMTP ETRN	option.

	      ODMR   Use the On-Demand Mail Relay ESMTP	profile.

       All  these  alternatives	 work in basically the same way	(communicating
       with standard server daemons to fetch mail already delivered to a mail-
       box on the server) except ETRN and ODMR.	 The ETRN mode allows  you  to
       ask  a compliant	ESMTP server (such as BSD sendmail at release 8.8.0 or
       higher) to immediately open a sender-SMTP connection to your client ma-
       chine and begin forwarding any items addressed to your  client  machine
       in  the server's	queue of undelivered mail.   The ODMR mode requires an
       ODMR-capable server and works similarly to ETRN,	except	that  it  does
       not require the client machine to have a	static DNS.

       -U | --uidl
	      (Keyword:	uidl)
	      Force  UIDL  use	(effective only	with POP3).  Force client-side
	      tracking of 'newness' of messages	(UIDL stands  for  "unique  ID
	      listing" and is described	in RFC1939).  Use with 'keep' to use a
	      mailbox  as a baby news drop for a group of users. The fact that
	      seen messages are	skipped	is logged,  unless  error  logging  is
	      done  through  syslog  while  running in daemon mode.  Note that
	      fetchmail	may automatically enable this option depending on  up-
	      stream  server  capabilities.  Note also that this option	may be
	      removed and forced enabled in a future  fetchmail	 version.  See
	      also: --idfile.

       --idle (since 6.3.3)
	      (Keyword:	idle, since before 6.0.0)
	      Enable IDLE use (effective only with IMAP). Note that this works
	      with  only  one  account	and  one folder	at a given time, other
	      folders or accounts will not be polled when idle is  in  effect!
	      While  the  idle	rcfile	keyword	 had been supported for	a long
	      time, the	--idle command-line option was added in	version	6.3.3.
	      IDLE use means that fetchmail tells the IMAP server to send  no-
	      tice of new messages, so they can	be retrieved sooner than would
	      be possible with regular polls.

       -P <portnumber> | --service <servicename>
	      (Keyword:	service) Since version 6.3.0.
	      The service option permits you to	specify	a service name to con-
	      nect  to.	  You  can specify a decimal port number here, if your
	      services database	lacks the required  service-port  assignments.
	      See  the	FAQ  item R12 and the --ssl documentation for details.
	      This replaces the	older --port option.

       Note that this does not magically switch	between	TLS-wrapped and	START-
       TLS modes, if you specify a port	number or service name	here  that  is
       TLS-wrapped, meaning it starts to negotiate TLS before sending applica-
       tion  data  in  the clear, you may need to specify --ssl	on the command
       line or ssl in your rcfile.

       --port <portnumber>
	      (Keyword:	port)
	      Obsolete version of --service that does not take service	names.
	      Note: this option	may be removed from a future version.

       --principal <principal>
	      (Keyword:	principal)
	      The  principal option permits you	to specify a service principal
	      for mutual authentication.  This is applicable to	POP3  or  IMAP
	      with  Kerberos 4 authentication only.  It	does not apply to Ker-
	      beros 5 or GSSAPI.  This option  may  be	removed	 in  a	future
	      fetchmail	version.

       -t <seconds> | --timeout	<seconds>
	      (Keyword:	timeout)
	      The timeout option allows	you to set a server-non-response time-
	      out  in seconds.	If a mail server does not send a greeting mes-
	      sage or respond to commands for the  given  number  of  seconds,
	      fetchmail	 will drop the connection to it.  Without such a time-
	      out fetchmail might hang until the  TCP  connection  times  out,
	      trying  to  fetch	mail from a down host, which may be very long.
	      This would be particularly annoying for a	fetchmail  running  in
	      the  background.	 There is a default timeout which fetchmail -V
	      will report.  If a given connection receives too	many  timeouts
	      in succession, fetchmail will consider it	wedged and stop	retry-
	      ing.   The  calling  user	will be	notified by email if this hap-
	      pens.

	      Beginning	with fetchmail 6.3.10, the SMTP	client uses the	recom-
	      mended minimum timeouts from  RFC-5321  while  waiting  for  the
	      SMTP/LMTP	 server	 it is talking to.  You	can raise the timeouts
	      even more, but you cannot	shorten	 them.	This  is  to  avoid  a
	      painful  situation  where	 fetchmail  has	been configured	with a
	      short timeout (a minute or less),	ships  a  long	message	 (many
	      MBytes)  to  the local MTA, which	then takes longer than timeout
	      to respond "OK", which it	eventually will; that would  mean  the
	      mail gets	delivered properly, but	fetchmail cannot notice	it and
	      will thus	re-fetch this big message over and over	again.

       --plugin	<command>
	      (Keyword:	plugin)
	      The  plugin  option allows you to	use an external	program	to es-
	      tablish the TCP connection.  This	is useful if you want  to  use
	      ssh,  or	need some special firewall setup.  The program will be
	      looked up	in $PATH and can optionally be passed  the  host  name
	      and  port	 as  arguments	using "%h" and "%p" respectively (note
	      that the interpolation logic is rather primitive,	and these  to-
	      kens must	be bounded by whitespace or beginning of string	or end
	      of string).  Fetchmail will write	to the plugin's	stdin and read
	      from the plugin's	stdout.

       --plugout <command>
	      (Keyword:	plugout)
	      Identical	 to  the plugin	option above, but this one is used for
	      the SMTP connections.

       -r <name> | --folder <name>
	      (Keyword:	folder[s])
	      Causes a specified non-default mail folder on  the  mail	server
	      (or  comma-separated list	of folders) to be retrieved.  The syn-
	      tax of the folder	name is	server-dependent.  This	option is  not
	      available	under POP3, ETRN, or ODMR.

       --tracepolls
	      (Keyword:	tracepolls)
	      Tell  fetchmail  to  poll	trace information in the form 'polling
	      account %s' and 'folder %s' to the Received line	it  generates,
	      where  the  %s parts are replaced	by the user's remote name, the
	      poll label, and the folder (mailbox) where  available  (the  Re-
	      ceived  header  also  normally includes the server's true	name).
	      This can be used to facilitate mail filtering based on  the  ac-
	      count it is being	received from. The folder information is writ-
	      ten only since version 6.3.4.

       --ssl  (Keyword:	ssl)
	      Causes  the  connection  to  the mail server to be encrypted via
	      SSL, by negotiating SSL directly after connecting	 (called  SSL-
	      wrapped  mode, or	Implicit TLS by	RFC-8314).  Please see the de-
	      scription	of --sslproto below!  More information is available in
	      the README.SSL file that ships with fetchmail.

	      Note that	even if	this option is omitted,	 fetchmail  may	 still
	      negotiate	 SSL  in-band  for  POP3  or IMAP, through the STLS or
	      STARTTLS feature.	 You can use the --sslproto option  to	modify
	      that behavior.

	      If no port is specified, the connection is attempted to the well
	      known  port  of  the  SSL	version	of the base protocol.  This is
	      generally	a different port than the port used by the base	proto-
	      col.  For	IMAP, this is port 143 for the clear protocol and port
	      993 for the SSL secured protocol;	for POP3, it is	port  110  for
	      the clear	text and port 995 for the encrypted variant.

	      If  your	system	lacks the corresponding	entries	from /etc/ser-
	      vices, see the --service option and  specify  the	 numeric  port
	      number  as  given	in the previous	paragraph (unless your ISP had
	      directed you to different	ports, which is	uncommon however).

       --sslcert <name>
	      (Keyword:	sslcert)
	      For certificate-based client authentication.  Some SSL encrypted
	      servers require client side keys and certificates	for  authenti-
	      cation.	In  most  cases, this is optional.  This specifies the
	      location of the public key certificate to	be  presented  to  the
	      server  at  the  time the	SSL session is established.  It	is not
	      required (but may	be provided) if	the server  does  not  require
	      it.   It	may  be	the same file as the private key (combined key
	      and certificate file) but	this  is  not  recommended.  Also  see
	      --sslkey below.

	      NOTE: If you use client authentication, the user name is fetched
	      from  the	 certificate's	CommonName  and	overrides the name set
	      with --user.

       --sslkey	<name>
	      (Keyword:	sslkey)
	      Specifies	the file name of the  client  side  private  SSL  key.
	      Some SSL encrypted servers require client	side keys and certifi-
	      cates  for  authentication.   In	most  cases, this is optional.
	      This specifies the location of the  private  key	used  to  sign
	      transactions  with the server at the time	the SSL	session	is es-
	      tablished.  It is	not required (but  may	be  provided)  if  the
	      server  does not require it. It may be the same file as the pub-
	      lic key (combined	key and	certificate file) but this is not rec-
	      ommended.

	      If a password is required	to unlock the key, it will be prompted
	      for at the time just prior to establishing the  session  to  the
	      server.  This can	cause some complications in daemon mode.

	      Also see --sslcert above.

       --sslproto <value>
	      (Keyword:	sslproto, NOTE:	semantic changes since v6.4.0)
	      This option has a	dual use, out of historic fetchmail behaviour.
	      It  controls  both the SSL/TLS protocol version and, if --ssl is
	      not specified, the STARTTLS behaviour (upgrading the protocol to
	      an SSL or	TLS connection in-band). Some other options  may  how-
	      ever make	TLS mandatory.

	      Only if this option and --ssl are	both missing for a poll, there
	      will  be	opportunistic  TLS  for	POP3 and IMAP, where fetchmail
	      will attempt to upgrade to TLSv1 or newer.

	      Recognized values	for --sslproto are  given  below.  You	should
	      normally	choose	one  of	 the  auto-negotiating	options, i. e.
	      'tls1.2+'	or 'auto' or one of the	other options ending in	a plus
	      (+) character.  Note that	depending on OpenSSL  library  version
	      and  configuration,  some	 options cause run-time	errors because
	      the requested SSL	or TLS versions	are not	supported by the  par-
	      ticular installed	OpenSSL	library.

	      'TLS1.2+'
		     (recommended).  Since v6.4.0. Require TLS.	Auto-negotiate
		     TLSv1.2 or	newer.

	      'auto' (default).	 Since	v6.4.0.	 Require  TLS.	Auto-negotiate
		     TLSv1  or	newer,	disable	 SSLv3	downgrade.  (fetchmail
		     6.3.26 and	older have auto-negotiated all protocols  that
		     their  OpenSSL  library  supported,  including the	broken
		     SSLv3).

	      '', the empty string
		     Disable STARTTLS. If --ssl	is given for the same  server,
		     log  an  error  and pretend that 'auto' had been used in-
		     stead.

	      'SSL23'
		     see 'auto'.

	      'SSL3' Require SSLv3 exactly. SSLv3 is broken, not supported  on
		     all systems, avoid	it if possible.	 This will make	fetch-
		     mail  negotiate  SSLv3  only, and is the only way besides
		     'SSL3+' to	have fetchmail 6.4.0 or	newer permit SSLv3.

	      'SSL3+'
		     same as 'auto', but permit	SSLv3 as  well.	 This  is  the
		     only  way besides 'SSL3' to have fetchmail	6.4.0 or newer
		     permit SSLv3.

	      'TLS1' Require TLSv1. This does not negotiate TLSv1.1 or	newer,
		     and  is  discouraged.  Replace by TLS1+ unless the	latter
		     chokes your server.

	      'TLS1+'
		     Since v6.4.0. See 'auto'.

	      'TLS1.1'
		     Since v6.4.0. Require TLS v1.1 exactly.

	      'TLS1.1+'
		     Since v6.4.0.  Require  TLS.  Auto-negotiate  TLSv1.1  or
		     newer.

	      'TLS1.2'
		     Since v6.4.0. Require TLS v1.2 exactly.

	      'TLS1.3'
		     Since v6.4.0. Require TLS v1.3 exactly.

	      'TLS1.3+'
		     Since  v6.4.0.  Require  TLS.  Auto-negotiate  TLSv1.3 or
		     newer.

	      Unrecognized parameters
		     are treated the same as 'auto'.

	      NOTE: you	should hardly ever need	to use anything	other than  ''
	      (to force	an unencrypted connection) or 'auto' (to enforce TLS).

       --sslcertck
	      (Keyword:	sslcertck, default enabled since v6.4.0)
	      --sslcertck causes fetchmail to require that SSL/TLS be used and
	      disconnect  unless  it can successfully negotiate	SSL or TLS, or
	      if it cannot successfully	verify and  validate  the  certificate
	      and  follow  it to a trust anchor	(or trusted root certificate).
	      The trust	anchors	are given as a set of local  trusted  certifi-
	      cates  (see  the	sslcertfile  and  sslcertpath options).	If the
	      server certificate cannot	be obtained or is not signed by	one of
	      the trusted ones (directly or indirectly), fetchmail  will  dis-
	      connect, regardless of the sslfingerprint	option.

       --nosslcertck
	      (Keyword:	no sslcertck, only in v6.4.X)
	      The  opposite  of	 --sslcertck, this is a	discouraged option. It
	      permits fetchmail	to continue connecting even if the server cer-
	      tificate failed the verification checks.	Should	only  be  used
	      together with --sslfingerprint.

       --sslcertfile <file>
	      (Keyword:	sslcertfile, since v6.3.17)
	      Sets the file fetchmail uses to look up local certificates.  The
	      default  is  empty.  This	can be given in	addition to --sslcert-
	      path below, and certificates specified in	--sslcertfile will  be
	      processed	before those in	--sslcertpath.	The option can be used
	      in addition to --sslcertpath.

	      The  file	 is  a	text  file.  It	 contains the concatenation of
	      trusted CA certificates in PEM format.

	      Note that	using this option will suppress	 loading  the  default
	      SSL  trusted CA certificates file	unless you set the environment
	      variable FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS to a  non-empty
	      value.

       --sslcertpath <directory>
	      (Keyword:	sslcertpath)
	      Sets the directory fetchmail uses	to look	up local certificates.
	      The  default  is	your  OpenSSL default directory. The directory
	      must be hashed the way OpenSSL expects it	- every	time  you  add
	      or  modify  a  certificate in the	directory, you need to use the
	      c_rehash tool (which comes with OpenSSL in the tools/ sub-direc-
	      tory). Also, after OpenSSL upgrades, you may need	to  run	 c_re-
	      hash.

	      This  can	be given in addition to	--sslcertfile above, which see
	      for precedence rules.

	      Note that	using this option will suppress	adding the default SSL
	      trusted CA certificates directory	unless you set the environment
	      variable FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS to a  non-empty
	      value.

       --sslcommonname <common name>
	      (Keyword:	sslcommonname; since v6.3.9)
	      Use  of this option is discouraged. Before using it, contact the
	      administrator of your upstream server and	ask for	a  proper  SSL
	      certificate  to be used. If that cannot be attained, this	option
	      can be used to specify the name (CommonName) that	fetchmail  ex-
	      pects  on	the server certificate.	 A correctly configured	server
	      will have	this set to the	host name by which it is reached,  and
	      by  default  fetchmail will expect as much. Use this option when
	      the CommonName is	set to some other value, to avoid the  "Server
	      CommonName  mismatch" warning, and only if the upstream server's
	      operator cannot be made to use proper certificates.

       --sslfingerprint	<fingerprint>
	      (Keyword:	sslfingerprint)
	      Specify the fingerprint of the server key	(an MD5	 hash  of  the
	      key)  in	hexadecimal  notation with colons separating groups of
	      two digits. The letter hex digits	must be	in upper case. This is
	      the format that fetchmail	uses to	report the fingerprint when an
	      SSL connection is	established. When this is specified, fetchmail
	      will compare the server key fingerprint with the given one,  and
	      the connection will fail if they do not match, regardless	of the
	      sslcertck	 setting.  The	connection will	also fail if fetchmail
	      cannot obtain an SSL certificate from the	server.	 This  can  be
	      used  to prevent man-in-the-middle attacks, but the finger print
	      from the server must be obtained or verified over	a secure chan-
	      nel, and certainly not over the same  Internet  connection  that
	      fetchmail	would use.

	      Using this option	will prevent printing certificate verification
	      errors as	long as	--nosslcertck is in effect.

	      To  obtain  the  fingerprint of a	certificate stored in the file
	      cert.pem,	try:

		   openssl x509	-in cert.pem -noout -md5 -fingerprint

	      For details, see x509(1ssl).

   Delivery Control Options
       -S <hosts> | --smtphost <hosts>
	      (Keyword:	smtp[host])
	      Specify a	hunt list of hosts to forward mail  to	(one  or  more
	      host names, comma-separated). Hosts are tried in list order; the
	      first  one that is up becomes the	forwarding target for the cur-
	      rent run.	 If this option	is not specified, 'localhost' is  used
	      as the default.  Each host name may have a port number following
	      the  host	name.  The port	number is separated from the host name
	      by a slash; the default port is "smtp".  If you specify  an  ab-
	      solute path name (beginning with a /), it	will be	interpreted as
	      the name of a UNIX socket	accepting LMTP connections (such as is
	      supported	by the Cyrus IMAP daemon) Example:

		   --smtphost server1,server2/2525,server3,/var/imap/socket/lmtp

	      This option can be used with ODMR, and will make fetchmail a re-
	      lay between the ODMR server and SMTP or LMTP receiver.

	      WARNING:	if  you	use address numeric IP addresses here, be sure
	      to use --smtpaddress or --smtpname (either of which see) with  a
	      valid SMTP address literal!

       --fetchdomains <hosts>
	      (Keyword:	fetchdomains)
	      In  ETRN or ODMR mode, this option specifies the list of domains
	      the server should	ship mail for once the	connection  is	turned
	      around.	The  default is	the FQDN of the	machine	running	fetch-
	      mail.

       -D <domain> | --smtpaddress <domain>
	      (Keyword:	smtpaddress)
	      Specify the domain to be appended	to addresses in	RCPT TO	 lines
	      shipped  to  SMTP.  When	this is	not specified, the name	of the
	      SMTP server (as specified	by --smtphost) is used	for  SMTP/LMTP
	      and 'localhost' is used for UNIX socket/BSMTP.

	      NOTE:  if	 you intend to use numeric addresses, or so-called ad-
	      dress literals per the SMTP standard, write them in proper  SMTP
	      syntax,  for  instance  --smtpaddress "[192.0.2.6]" or --smtpad-
	      dress "[IPv6:2001:DB8::6]".

       --smtpname <user@domain>
	      (Keyword:	smtpname)
	      Specify the domain and user to be	put in RCPT TO	lines  shipped
	      to  SMTP.	  The  default	user is	the current local user.	Please
	      also see the  NOTE  about	 --smtpaddress	and  address  literals
	      above.

       -Z <nnn>	| --antispam <nnn[, nnn]...>
	      (Keyword:	antispam)
	      Specifies	 the list of numeric SMTP errors that are to be	inter-
	      preted as	a spam-block response from the listener.  A  value  of
	      -1  disables this	option.	 For the command-line option, the list
	      values should be comma-separated.	 Note that the antispam	values
	      only apply to "MAIL FROM"	responses in the  SMTP/LMTP  dialogue,
	      but  several  MTAs (Postfix in its default configuration,	qmail)
	      defer the	anti-spam response code	until after the	RCPT TO. --an-
	      tispam does not work in these circumstances.  Also  see  --soft-
	      bounce (default) and its inverse.

       -m <command> | --mda <command>
	      (Keyword:	mda)
	      This option lets fetchmail use a Message or Local	Delivery Agent
	      (MDA or LDA) directly, rather than forward via SMTP or LMTP.

	      To  avoid	losing mail, use this option only with MDAs like mail-
	      drop or MTAs like	sendmail that exit with	a  nonzero  status  on
	      disk-full	 and  other  delivery errors; the nonzero status tells
	      fetchmail	that delivery failed and prevents the message from be-
	      ing deleted on the server.

	      If fetchmail is running as root, it sets its user	id  while  de-
	      livering	mail  through  an  MDA	as follows:  First, the	FETCH-
	      MAILUSER,	LOGNAME, and USER environment variables	are checked in
	      this order. The value of the first variable from his  list  that
	      is  defined  (even  if  it is empty!) is looked up in the	system
	      user database. If	none of	the variables  is  defined,  fetchmail
	      will  use	 the  real  user id it was started with. If one	of the
	      variables	was defined, but the user stated there is  not	found,
	      fetchmail	 continues running as root, without checking remaining
	      variables	on the list.  Practically, this	means that if you  run
	      fetchmail	as root	(not recommended), it is most useful to	define
	      the  FETCHMAILUSER environment variable to set the user that the
	      MDA should run as. Some MDAs (such as maildrop) are designed  to
	      be  setuid root and setuid to the	recipient's user id, so	you do
	      not lose functionality this way even when	running	 fetchmail  as
	      unprivileged user.  Check	the MDA's manual for details.

	      Some  possible  MDAs  are	 "/usr/sbin/sendmail  -i  -f %F	-- %T"
	      (Note: some several older	or vendor sendmail versions mistake --
	      for an address, rather than an indicator to mark the end of  the
	      option  arguments), "/usr/bin/deliver" and "/usr/bin/maildrop -d
	      %T".  Local delivery addresses will be  inserted	into  the  MDA
	      command wherever you place a %T; the mail	message's From address
	      will be inserted where you place an %F.

	      Do  NOT  enclose the %F or %T string in single quotes!  For both
	      %T and %F, fetchmail encloses the	 addresses  in	single	quotes
	      ('),  after  removing any	single quotes they may contain,	before
	      the MDA command is passed	to the shell.

	      Do NOT use an MDA	invocation that	dispatches on the contents  of
	      To/Cc/Bcc, like "sendmail	-i -t" or "qmail-inject", it will cre-
	      ate mail loops and bring the just	wrath of many postmasters down
	      upon  your head.	This is	one of the most	frequent configuration
	      errors!

	      Also, do not try to combine multidrop mode with an MDA  such  as
	      maildrop	that can only accept one address, unless your upstream
	      stores one copy of the message per recipient and transports  the
	      envelope recipient in a header; you will lose mail.

	      The  well-known  procmail(1)  package  is	very hard to configure
	      properly,	it has a very nasty "fall through to  the  next	 rule"
	      behavior on delivery errors (even	temporary ones,	such as	out of
	      disk  space  if  another	user's	mail daemon copies the mailbox
	      around to	purge old messages), so	your mail will end up  in  the
	      wrong mailbox sooner or later. The proper	procmail configuration
	      is outside the scope of this document. Using maildrop(1) is usu-
	      ally  much easier, and many users	find the filter	syntax used by
	      maildrop easier to understand.

	      Finally, we strongly advise that you do  not  use	 qmail-inject.
	      The  command  line  interface  is	non-standard without providing
	      benefits for typical use,	and fetchmail makes no attempts	to ac-
	      commodate	qmail-inject's deviations from the standard.  Some  of
	      qmail-inject's command-line and environment options are actually
	      dangerous	 and  can cause	broken threads,	non-detected duplicate
	      messages and forwarding loops.

       --lmtp (Keyword:	lmtp)
	      Cause delivery via LMTP (Local Mail Transfer Protocol).  A  ser-
	      vice  host and port must be explicitly specified on each host in
	      the smtphost hunt	list (see above) if this option	 is  selected;
	      the  default  port  25 will (in accordance with RFC 2033)	not be
	      accepted.

       --bsmtp <filename>
	      (Keyword:	bsmtp)
	      Append fetched mail to a BSMTP file.  This simply	 contains  the
	      SMTP commands that would normally	be generated by	fetchmail when
	      passing mail to an SMTP listener daemon.

	      An  argument of '-' causes the SMTP batch	to be written to stan-
	      dard output, which is of limited use: this only makes sense  for
	      debugging, because fetchmail's regular output is interspersed on
	      the  same	 channel,  so  this is not suitable for	mail delivery.
	      This special mode	may be removed in a later release.

	      Note that	fetchmail's reconstruction of MAIL FROM	 and  RCPT  TO
	      lines is not guaranteed correct; the caveats discussed under THE
	      USE AND ABUSE OF MULTIDROP MAILBOXES below apply.	 This mode has
	      precedence before	--mda and SMTP/LMTP.

       --bad-header {reject|accept}
	      (Keyword:	bad-header; since v6.3.15)
	      Specify  how  fetchmail  is  supposed to treat messages with bad
	      headers, i.e., headers with bad syntax. Traditionally, fetchmail
	      has rejected  such  messages,  but  some	distributors  modified
	      fetchmail	 to accept them. You can now configure fetchmail's be-
	      haviour per server.

   Resource Limit Control Options
       -l <maxbytes> | --limit <maxbytes>
	      (Keyword:	limit)
	      Takes a maximum octet size argument, where 0 is the default  and
	      also the special value designating "no limit".  If nonzero, mes-
	      sages larger than	this size will not be fetched and will be left
	      on  the  server  (in  foreground sessions, the progress messages
	      will note	that they are "oversized").   If  the  fetch  protocol
	      permits  (in particular, under IMAP or POP3 without the fetchall
	      option) the message will not be marked seen.

	      An explicit --limit of 0 overrides any limits set	 in  your  run
	      control  file.  This  option  is	intended  for those needing to
	      strictly control fetch time due to expensive and variable	 phone
	      rates.

	      Combined	with  --limitflush, it can be used to delete oversized
	      messages waiting on a server.  In	daemon mode, oversize  notifi-
	      cations  are  mailed to the calling user (see the	--warnings op-
	      tion). This option does not work with ETRN or ODMR.

       -w <interval> | --warnings <interval>
	      (Keyword:	warnings)
	      Takes an interval	in seconds.  When you call  fetchmail  with  a
	      'limit'  option  in  daemon  mode, this controls the interval at
	      which warnings about oversized messages are mailed to the	 call-
	      ing  user	 (or  the  user	specified by the 'postmaster' option).
	      One such notification is always mailed at	the end	of  the	 first
	      poll that	the oversized message is detected.  Thereafter,	re-no-
	      tification  is  suppressed  until	 after	the  warning  interval
	      elapses (it will take place at the end of	 the  first  following
	      poll).

       -b <count> | --batchlimit <count>
	      (Keyword:	batchlimit)
	      Specify  the  maximum number of messages that will be shipped to
	      an SMTP listener before the connection is	deliberately torn down
	      and rebuilt (defaults to 0,  meaning  no	limit).	  An  explicit
	      --batchlimit  of	0 overrides any	limits set in your run control
	      file.  While sendmail(8) normally	initiates delivery of  a  mes-
	      sage  immediately	 after	receiving the message terminator, some
	      SMTP listeners are not so	prompt.	 MTAs like smail(8)  may  wait
	      till the delivery	socket is shut down to deliver.	 This may pro-
	      duce  annoying  delays  when  fetchmail is processing very large
	      batches.	Setting	the batch limit	to some	nonzero	size will pre-
	      vent these delays.  This option does not work with ETRN or ODMR.

       -B <number> | --fetchlimit <number>
	      (Keyword:	fetchlimit)
	      Limit the	number of messages accepted from a given server	 in  a
	      single poll.  By default there is	no limit. An explicit --fetch-
	      limit  of	 0  overrides any limits set in	your run control file.
	      This option does not work	with ETRN or ODMR.

       --fetchsizelimit	<number>
	      (Keyword:	fetchsizelimit)
	      Limit the	number of sizes	of  messages  accepted	from  a	 given
	      server in	a single transaction.  This option is useful in	reduc-
	      ing  the	delay in downloading the first mail when there are too
	      many mails in the	mailbox.  By default, the limit	 is  100.   If
	      set  to  0,  sizes  of all messages are downloaded at the	start.
	      This option does not work	with ETRN or ODMR.  For	POP3, the only
	      valid non-zero value is 1.

       --fastuidl <number>
	      (Keyword:	fastuidl)
	      Do a binary instead of linear search for the first  unseen  UID.
	      Binary  search  avoids  downloading  the UIDs of all mails. This
	      saves time (especially in	daemon	mode)  where  downloading  the
	      same  set	of UIDs	in each	poll is	a waste	of bandwidth. The num-
	      ber 'n' indicates	how rarely a linear search should be done.  In
	      daemon  mode,  linear  search  is	 used  once followed by	binary
	      searches in 'n-1'	polls if 'n' is	greater	than 1;	binary	search
	      is  always used if 'n' is	1; linear search is always used	if 'n'
	      is 0. In non-daemon mode,	binary search is used  if  'n'	is  1;
	      otherwise	 linear	search is used.	The default value of 'n' is 4.
	      This option works	with POP3 only.

       -e <count> | --expunge <count>
	      (Keyword:	expunge)
	      Arrange for deletions to be made final after a given  number  of
	      messages.	  Under	 POP2 or POP3, fetchmail cannot	make deletions
	      final without sending QUIT and ending the	session	--  with  this
	      option  on,  fetchmail  will break a long	mail retrieval session
	      into multiple sub-sessions, sending QUIT after each sub-session.
	      This is a	good defense against line drops	on POP3	servers.   Un-
	      der  IMAP,  fetchmail  normally  issues an EXPUNGE command after
	      each deletion in order to	force the deletion to be done  immedi-
	      ately.   This  is	 safest	 when your connection to the server is
	      flaky and	expensive, as it avoids	re-sending duplicate mail  af-
	      ter a line hit.  However,	on large mailboxes the overhead	of re-
	      indexing after every message can slam the	server pretty hard, so
	      if  your	connection  is reliable	it is good to do expunges less
	      frequently.  Also	note that some servers enforce a  delay	 of  a
	      few seconds after	each quit, so fetchmail	may not	be able	to get
	      back  in immediately after an expunge -- you may see "lock busy"
	      errors if	this happens. If you specify this option to an integer
	      N, it tells fetchmail  to	 only  issue  expunges	on  every  Nth
	      delete.  An argument of zero suppresses expunges entirely	(so no
	      expunges at all will be done until the end of run).  This	option
	      does not work with ETRN or ODMR.

   Authentication Options
       -u <name> | --user <name> | --username <name>
	      (Keyword:	user[name])
	      Specifies	 the user identification to be used when logging in to
	      the mail server.	The appropriate	user  identification  is  both
	      server  and  user-dependent.   The default is your login name on
	      the client machine that is running fetchmail.  See USER  AUTHEN-
	      TICATION below for a complete description.

       -I <specification> | --interface	<specification>
	      (Keyword:	interface)
	      Require  that  a specific	interface device be up and have	a spe-
	      cific local or remote IPv4 (IPv6 is not supported	by this	option
	      yet) address (or range) before polling.  Frequently fetchmail is
	      used over	a transient point-to-point TCP/IP link established di-
	      rectly to	a mail server via SLIP or PPP.	That is	 a  relatively
	      secure channel.  But when	other TCP/IP routes to the mail	server
	      exist  (e.g.,  when  the link is connected to an alternate ISP),
	      your username and	password may be	vulnerable to snooping	(espe-
	      cially when daemon mode automatically polls for mail, shipping a
	      clear  password  over  the  net  at predictable intervals).  The
	      --interface option may be	used to	prevent	this.  When the	speci-
	      fied link	is not up or is	not connected to  a  matching  IP  ad-
	      dress, polling will be skipped.  The format is:

		   interface/iii.iii.iii.iii[/mmm.mmm.mmm.mmm]

	      The  field  before  the first slash is the interface name	(i.e.,
	      sl0, ppp0	etc.).	The field before the second slash is  the  ac-
	      ceptable IP address.  The	field after the	second slash is	a mask
	      which  specifies	a range	of IP addresses	to accept.  If no mask
	      is present 255.255.255.255 is assumed (i.e.,  an	exact  match).
	      This option is currently only supported under Linux and FreeBSD.
	      Please  see  the	monitor	section	for below for FreeBSD specific
	      information.

	      Note that	this option may	be removed  from  a  future  fetchmail
	      version.

       -M <interface> |	--monitor <interface>
	      (Keyword:	monitor)
	      Daemon  mode  can	 cause transient links which are automatically
	      taken down after a period	of inactivity (e.g., PPP links)	to re-
	      main up indefinitely.  This option identifies  a	system	TCP/IP
	      interface	 to be monitored for activity.	After each poll	inter-
	      val, if the link is up but no other activity has occurred	on the
	      link, then the poll will be skipped.  However, when fetchmail is
	      woken up by a signal, the	monitor	check is skipped and the  poll
	      goes  through  unconditionally.	This  option is	currently only
	      supported	under Linux and	FreeBSD.  For the monitor  and	inter-
	      face  options  to	 work  for  non	 root users under FreeBSD, the
	      fetchmail	binary must be installed setgid	kmem.  This would be a
	      security hole, but fetchmail runs	with the effective GID set  to
	      that  of	the  kmem group	only when interface data is being col-
	      lected.

	      Note that	this option may	be removed  from  a  future  fetchmail
	      version.

       --auth <type>
	      (Keyword:	auth[enticate])
	      This  option  permits you	to specify an authentication type (see
	      USER AUTHENTICATION below	for details).  The possible values are
	      any, password, kerberos_v5, kerberos (or,	for  excruciating  ex-
	      actness,	kerberos_v4),  gssapi,	cram-md5, otp, ntlm, msn (only
	      for POP3), external (only	IMAP) and ssh.	When any (the default)
	      is specified, fetchmail tries first methods that do not  require
	      a	 password (EXTERNAL, GSSAPI, KERBEROS IV, KERBEROS 5); then it
	      looks for	methods	that mask your password	(CRAM-MD5, NTLM, X-OTP
	      -	note that MSN is  only	supported  for	POP3,  but  not	 auto-
	      probed);	and  only  if the server does not support any of those
	      will it ship your	password unencrypted.	Other  values  may  be
	      used to force various authentication methods: ssh	suppresses au-
	      thentication and is thus useful for IMAP PREAUTH (if you are us-
	      ing  a secure --plugin, for instance, a properly configured ssh,
	      you may also need	to set --sslproto '' or, in the	 rcfile,  ssl-
	      proto '',	 in order to avoid fetchmail negotiating STARTTLS over
	      SSH).  external suppresses authentication	and is thus useful for
	      IMAP EXTERNAL.  Any value	other than password,  cram-md5,	 ntlm,
	      msn or otp suppresses fetchmail's	normal inquiry for a password.
	      Specify  ssh  when you are using an end-to-end secure connection
	      such as an ssh tunnel (in	this case you may also want to specify
	      --sslproto '', which see); specify external  when	 you  use  TLS
	      with  client authentication and specify gssapi or	kerberos_v4 if
	      you are using a protocol variant	that  employs  GSSAPI  or  K4.
	      Choosing	KPOP protocol automatically selects Kerberos authenti-
	      cation.  This option does	not work with  ETRN.   GSSAPI  service
	      names  are  in  line  with  RFC-2743 and IANA registrations, see
	      Generic Security Service	Application  Program  Interface	 (GSS-
	      API)/Kerberos/Simple  Authentication  and	 Security Layer	(SASL)
	      Service Names  <https://www.iana.org/assignments/gssapi-service-
	      names/>.

   Miscellaneous Options
       -f <pathname> | --fetchmailrc <pathname>
	      Specify  a  non-default  name for	the ~/.fetchmailrc run control
	      file.  The pathname argument must	be either "-" (a single	 dash,
	      meaning  to  read	 the  configuration  from standard input) or a
	      filename.	 Unless	the --version option is	also on, a named  file
	      argument	 must	have   permissions  no	more  open  than  0700
	      (u=rwx,g=,o=) or else be /dev/null.

       -i <pathname> | --idfile	<pathname>
	      (Keyword:	idfile)
	      Specify an alternate name	for the	.fetchids file	used  to  save
	      message  UIDs.  NOTE: since fetchmail 6.3.0, write access	to the
	      directory	containing the idfile is required, as fetchmail	writes
	      a	temporary file and renames it into the place of	the  real  id-
	      file  only  if the temporary file	has been written successfully.
	      This avoids the truncation of idfiles when running out  of  disk
	      space.

       --pidfile <pathname>
	      (Keyword:	pidfile; since fetchmail v6.3.4)
	      Override	the default location of	the PID	file that is used as a
	      lock file.  Default: see "ENVIRONMENT"  below.  Note  that  many
	      places  in  the  code and	documentation, the term	"lock file" is
	      used.  This file contains	the process ID of the  running	fetch-
	      mail  on the first line and potentially the daemon interval on a
	      second line.

       -n | --norewrite
	      (Keyword:	no rewrite)
	      Normally,	fetchmail edits	RFC-822	address	headers	(To, From, Cc,
	      Bcc, and Reply-To) in fetched mail so that any mail IDs local to
	      the server are expanded to full addresses	(@ and the mail	server
	      host name	are appended).	This enables replies on	the client  to
	      get  addressed correctly (otherwise your mailer might think they
	      should be	addressed to local  users  on  the  client  machine!).
	      This  option  disables the rewrite.  (This option	is provided to
	      pacify people who	are paranoid about having  an  MTA  edit  mail
	      headers  and  want to know they can prevent it, but it is	gener-
	      ally not a good idea to actually turn off	rewrite.)  When	 using
	      ETRN or ODMR, the	rewrite	option is ineffective.

       -E <line> | --envelope <line>
	      (Keyword:	envelope; Multidrop only)
	      In the configuration file, an enhanced syntax is used:
	      envelope [<count>] <line>

	      This  option  changes  the header	fetchmail assumes will carry a
	      copy of the mail's envelope address.  Normally this is  'X-Enve-
	      lope-To'.	  Other	 typically found headers to carry envelope in-
	      formation	are 'X-Original-To' and	 'Delivered-To'.   Now,	 since
	      these  headers  are  not	standardized, practice varies. See the
	      discussion of multidrop address handling below.	As  a  special
	      case,  'envelope	"Received"'  enables parsing of	sendmail-style
	      Received lines.  This is the default, but	discouraged because it
	      is not fully reliable.

	      Note that	fetchmail expects the Received-line to be  in  a  spe-
	      cific  format: It	must contain "by host for address", where host
	      must match one of	the mail server	names  that  fetchmail	recog-
	      nizes for	the account in question.

	      The optional count argument (only	available in the configuration
	      file) determines how many	header lines of	this kind are skipped.
	      A	 count of 1 means: skip	the first, take	the second. A count of
	      2	means: skip the	first and second, take the third, and so on.

       -Q <prefix> | --qvirtual	<prefix>
	      (Keyword:	qvirtual; Multidrop only)
	      The string prefix	assigned to this option	will be	 removed  from
	      the  user	 name  found in	the header specified with the envelope
	      option (before  doing  multidrop	name  mapping  or  localdomain
	      checking,	if either is applicable). This option is useful	if you
	      are using	fetchmail to collect the mail for an entire domain and
	      your  ISP	 (or  your  mail redirection provider) is using	qmail.
	      One of the basic features	of qmail is the	Delivered-To:  message
	      header.  Whenever	qmail delivers a message to a local mailbox it
	      puts  the	 username  and	host name of the envelope recipient on
	      this line.  The major reason for this is to prevent mail	loops.
	      To  set  up qmail	to batch mail for a disconnected site the ISP-
	      mailhost will have normally put that site	in its	'Virtualhosts'
	      control  file  so	it will	add a prefix to	all mail addresses for
	      this site. This results in mail sent to 'username@userhost.user-
	      dom.dom.com' having a Delivered-To: line of the form:

	      Delivered-To: mbox-userstr-username@userhost.example.com

	      The ISP can make the 'mbox-userstr-' prefix anything they	choose
	      but a string matching the	user host name is  likely.   By	 using
	      the option 'envelope Delivered-To:' you can make fetchmail reli-
	      ably  identify  the original envelope recipient, but you have to
	      strip the	'mbox-userstr-'	prefix to deliver to the correct user.
	      This is what this	option is for.

       --configdump
	      Parse the	~/.fetchmailrc file, interpret	any  command-line  op-
	      tions  specified,	 and  dump  a configuration report to standard
	      output.  The configuration report	is a data structure assignment
	      in the language Python.  This option is meant to be used with an
	      interactive ~/.fetchmailrc editor	like fetchmailconf, written in
	      Python.

       -y | --yydebug
	      Enables parser debugging,	this option is meant to	be used	by de-
	      velopers only.

   Removed Options
       -T | --netsec
	      Removed before version 6.3.0, the	required underlying inet6_apps
	      library had been discontinued and	is no longer available.

USER AUTHENTICATION AND	ENCRYPTION
       All modes except	ETRN require  authentication  of  the  client  to  the
       server.	 Normal	user authentication in fetchmail is very much like the
       authentication mechanism	of ftp(1).  The	correct	user-id	 and  password
       depend upon the underlying security system at the mail server.

       If the mail server is a Unix machine on which you have an ordinary user
       account,	 your regular login name and password are used with fetchmail.
       If you use the same login name on both the server and  the  client  ma-
       chines, you needn't worry about specifying a user-id with the -u	option
       -- the default behavior is to use your login name on the	client machine
       as  the	user-id	 on  the server	machine.  If you use a different login
       name on the server machine, specify that	login name with	the -u option.
       E.g., if	your login name	is 'jsmith' on a  machine  named  'mailgrunt',
       you would start fetchmail as follows:

	      fetchmail	-u jsmith mailgrunt

       The default behavior of fetchmail is to prompt you for your mail	server
       password	 before	the connection is established.	This is	the safest way
       to use fetchmail	and ensures that your password	will  not  be  compro-
       mised.  You may also specify your password in your ~/.fetchmailrc file.
       This is convenient when using fetchmail in daemon mode or with scripts.

   Using netrc files
       If you do not specify a password, and fetchmail cannot extract one from
       your ~/.fetchmailrc file, it will look for a ~/.netrc file in your home
       directory before	requesting one interactively; if an entry matching the
       mail  server  is	found in that file, the	password will be used.	Fetch-
       mail first looks	for a match on poll name; if it	finds none, it	checks
       for  a  match  on via name.  See	the ftp(1) man page for	details	of the
       syntax of the ~/.netrc file.  To	show a	practical  example,  a	.netrc
       might look like this:

	      machine hermes.example.org
	      login joe
	      password topsecret

       You  can	 repeat	this block with	different user information if you need
       to provide more than one	password.

       This feature may	allow you to avoid duplicating password	information in
       more than one file.

       On mail servers that do not provide ordinary user accounts, your	 user-
       id  and	password are usually assigned by the server administrator when
       you apply for a mailbox on the server.  Contact your server administra-
       tor if you do not know the correct user-id and password for your	 mail-
       box account.

   Secure Socket Layers	(SSL) and Transport Layer Security (TLS)
       All  retrieval protocols	can use	SSL or TLS wrapping for	the transport.
       Additionally, POP3 and IMAP retrieval can  also	negotiate  SSL/TLS  by
       means of	STARTTLS (or STLS).

       You  can	access TLS-encrypted services by specifying the	options	start-
       ing with	--ssl, such as --ssl,  --sslproto,  --sslcertck,  and  others.
       You  can	 also  do  this	 using	the  corresponding user	options	in the
       .fetchmailrc file.  Some	services, such as POP3 and IMAP, have  differ-
       ent  well  known	ports defined for the SSL encrypted services.  The en-
       crypted ports will be selected automatically when SSL is	enabled	and no
       explicit	port is	specified.   Also, the	--sslcertck  command  line  or
       sslcertck  run  control file option should be used to force strict cer-
       tificate	checking with older fetchmail versions - see below.

       If TLS or SSL is	not configured,	fetchmail will usually	still  try  to
       use  STARTTLS  somewhat	opportunistically.  In	practice,  is it still
       mandatory because --sslcertck is	a default setting and  implicitly  re-
       quires STARTTLS.

       STARTTLS	can be enforced	by using --sslproto auto and defeated by using
       --sslproto  ''.	 STARTTLS  connections	use the	same port as the unen-
       crypted version of the protocol and negotiate TLS via special  command.
       The  --sslcertck	 command  line	or  sslcertck  run control file	option
       should be used to force strict certificate checking - see below.

       --sslcertck is recommended: When	connecting to an SSL or	TLS  encrypted
       server, the server presents a certificate to the	client for validation.
       The  certificate	 is checked to verify that the common name in the cer-
       tificate	matches	the name of the	server being contacted	and  that  the
       effective  and  expiration dates	in the certificate indicate that it is
       currently valid.	 If any	of these checks	fail,  a  warning  message  is
       printed,	but the	connection continues.  The server certificate does not
       need  to	 be  signed  by	any specific Certifying	Authority and may be a
       "self-signed" certificate. If the --sslcertck command  line  option  or
       sslcertck run control file option is used, fetchmail will instead abort
       if  any	of  these  checks fail,	because	it must	assume that there is a
       man-in-the-middle attack	in this	scenario, hence	fetchmail must not ex-
       pose clear-text passwords. Use of the sslcertck or  --sslcertck	option
       is therefore advised; it	has become the default in fetchmail 6.4.0.

       Some  SSL  encrypted  servers may request a client side certificate.  A
       client side public SSL certificate and private SSL key  may  be	speci-
       fied.   If  requested  by the server, the client	certificate is sent to
       the server for validation.  Some	servers	may  require  a	 valid	client
       certificate and may refuse connections if a certificate is not provided
       or  if  the  certificate	is not valid.  Some servers may	require	client
       side certificates be signed by a	recognized Certifying Authority.   The
       format  for the key files and the certificate files is that required by
       the underlying SSL libraries (OpenSSL in	the general case).

       A word of care about the	use of SSL: While above	mentioned  setup  with
       self-signed  server  certificates  retrieved over the wires can protect
       you from	a passive eavesdropper,	it does	not help against an active at-
       tacker. It is clearly an	improvement  over  sending  the	 passwords  in
       clear, but you should be	aware that a man-in-the-middle attack is triv-
       ially   possible	  (in	particular   with   tools   such   as	dsniff
       <https://monkey.org/~dugsong/dsniff/>).	 Use  of  strict   certificate
       checking	 with  a  certification	 authority  recognized	by  server and
       client, or perhaps of an	SSH tunnel (see	below for  some	 examples)  is
       preferable if you care seriously	about the security of your mailbox and
       passwords.

POP3 VARIANTS
       Early versions of POP3 (RFC1081,	RFC1225) supported a crude form	of in-
       dependent  authentication  using	 the  .rhosts  file on the mail	server
       side.  Under this RPOP variant, a fixed per-user	 ID  equivalent	 to  a
       password	 was  sent  in	clear over a link to a reserved	port, with the
       command RPOP rather than	PASS to	alert the server  that	it  should  do
       special	checking.   RPOP  is  supported	 by fetchmail (you can specify
       'protocol RPOP' to have the program send	'RPOP' rather than 'PASS') but
       its use is strongly discouraged,	and support will be removed from a fu-
       ture fetchmail version.	This facility was vulnerable to	 spoofing  and
       was withdrawn in	RFC1460.

       RFC1460	introduced  APOP authentication.  In this variant of POP3, you
       register	an APOP	password on your server	host  (on  some	 servers,  the
       program to do this is called popauth(8)).  You put the same password in
       your ~/.fetchmailrc file.  Each time fetchmail logs in, it sends	an MD5
       hash of your password and the server greeting time to the server, which
       can verify it by	checking its authorization database.

       Note  that  APOP	 is no longer considered resistant against man-in-the-
       middle attacks.

   RETR	or TOP
       fetchmail makes some efforts to make the	server	believe	 messages  had
       not  been  retrieved,  by  using	the TOP	command	with a large number of
       lines when possible.  TOP is a command that retrieves the  full	header
       and  a  fetchmail-specified  amount  of	body lines. It is optional and
       therefore not implemented by all	servers, and some are known to	imple-
       ment it improperly. On many servers however, the	RETR command which re-
       trieves	the  full  message  with header	and body, sets the "seen" flag
       (for instance, in a web interface), whereas the TOP command does	not do
       that.

       fetchmail will always use  the  RETR  command  if  "fetchall"  is  set.
       fetchmail will also use the RETR	command	if "keep" is set and "uidl" is
       unset.	Finally,  fetchmail  will  use the RETR	command	on Maillennium
       POP3/PROXY servers (used	by Comcast) to avoid a deliberate  TOP	misin-
       terpretation in this server that	causes message corruption.

       In  all	other  cases, fetchmail	will use the TOP command. This implies
       that in "keep" setups, "uidl" must be set if "TOP" is desired.

       Note that this description is true for the current  version  of	fetch-
       mail,  but  the	behavior may change in future versions.	In particular,
       fetchmail may prefer the	RETR command because the  TOP  command	causes
       much grief on some servers and is only optional.

ALTERNATE AUTHENTICATION FORMS/METHODS
       If  your	fetchmail was built with Kerberos support and you specify Ker-
       beros authentication (either with --auth	or the .fetchmailrc option au-
       thenticate kerberos_v4) it will try to get a Kerberos ticket  from  the
       mail  server  at	the start of each query.  Note:	if either the pollname
       or via name is 'hesiod',	fetchmail will try to use Hesiod  to  look  up
       the mail	server.

       If  you use POP3	or IMAP	with GSSAPI authentication, fetchmail will ex-
       pect the	server to have RFC1731-	or RFC1734-conforming GSSAPI  capabil-
       ity,  and  will	use it.	 Currently this	has only been tested over Ker-
       beros 5,	so you are expected to already have a ticket-granting  ticket.
       You  may	 pass  a username different from your principal	name using the
       standard	--user command or by the .fetchmailrc option user.

       If your IMAP daemon returns the PREAUTH response	in its greeting	 line,
       fetchmail  will	notice	this  and skip the normal authentication step.
       This can	be useful, e.g., if you	start imapd explicitly using ssh.   In
       this  case  you can declare the authentication value 'ssh' on that site
       entry to	stop .fetchmail	from asking you	for a password when it	starts
       up.

       If you use client authentication	with TLS1 and your IMAP	daemon returns
       the AUTH=EXTERNAL response, fetchmail will notice this and will use the
       authentication  shortcut	and will not send the passphrase. In this case
       you can declare the authentication value	'external'
	on that	site to	stop fetchmail from asking you for a password when  it
       starts up.

       If  you are using POP3, and the server issues a one-time-password chal-
       lenge conforming	to RFC1938, fetchmail will use your password as	a pass
       phrase to generate the required response. This avoids  sending  secrets
       over the	net unencrypted.

       Compuserve's  RPA  authentication  is  supported. If you	compile	in the
       support,	fetchmail will try to perform an RPA  pass-phrase  authentica-
       tion  instead  of  sending  over	the password unencrypted if it detects
       "@compuserve.com" in the	host name.

       If you are using	IMAP, Microsoft's NTLM	authentication	(used  by  Mi-
       crosoft	Exchange)  is supported. If you	compile	in the support,	fetch-
       mail will try to	perform	an NTLM	 authentication	 (instead  of  sending
       over the	password unencrypted) whenever the server returns AUTH=NTLM in
       its  capability	response.  Specify a user option value that looks like
       'user@domain': the part to the left of the @  will  be  passed  as  the
       username	and the	part to	the right as the NTLM domain.

   ESMTP AUTH
       fetchmail  also	supports  authentication  to  the  ESMTP server	on the
       client side according to	RFC 2554.  You	can  specify  a	 name/password
       pair  to	be used	with the keywords 'esmtpname' and 'esmtppassword'; the
       former defaults to the username of the calling user.

DAEMON MODE
   Introducing the daemon mode
       In daemon mode, fetchmail puts itself into the background and runs for-
       ever, querying each specified  host  and	 then  sleeping	 for  a	 given
       polling interval.

   Starting the	daemon mode
       There  are  several  ways to make fetchmail work	in daemon mode.	On the
       command line, --daemon <interval> or -d <interval> option  runs	fetch-
       mail  in	 daemon	 mode.	You must specify a numeric argument which is a
       polling interval	(time to wait after completing a whole poll cycle with
       the last	server and before starting the next poll cycle with the	 first
       server) in seconds.

       Example:	simply invoking

	      fetchmail	-d 900

       will,  therefore,  poll	all the	hosts described	in your	~/.fetchmailrc
       file (except those explicitly excluded with the 'skip' verb) a bit less
       often than once every 15	minutes	(exactly: 15 minutes + time  that  the
       poll takes).

       It  is  also  possible to set a polling interval	in your	~/.fetchmailrc
       file by saying 'set daemon <interval>', where <interval>	is an  integer
       number of seconds.  If you do this, fetchmail will always start in dae-
       mon mode	unless you override it with the	command-line option --daemon 0
       or -d0.

       Only  one  daemon process is permitted per user;	in daemon mode,	fetch-
       mail sets up a per-user lock file to guarantee this.  (You can  however
       cheat  and  set the FETCHMAILHOME environment variable to overcome this
       setting,	but in that case, it is	your responsibility to make  sure  you
       are not polling the same	server with two	processes at the same time.)

   Awakening the background daemon
       Normally,  calling  fetchmail  with  a daemon in	the background sends a
       wake-up signal to the daemon and	quits without output.  The  background
       daemon  then  starts its	next poll cycle	immediately.  The wake-up sig-
       nal, SIGUSR1, can also be sent manually.	The wake-up action also	clears
       any 'wedged' flags indicating  that  connections	 have  wedged  due  to
       failed authentication or	multiple timeouts.

   Terminating the background daemon
       The  option  -q or --quit will kill a running daemon process instead of
       waking it up (if	there is no such process, fetchmail will notify	 you).
       If  the	--quit option appears last on the command line,	fetchmail will
       kill the	running	daemon process and  then  quit.	 Otherwise,  fetchmail
       will first kill a running daemon	process	and then continue running with
       the other options.

   Useful options for daemon mode
       The -L <filename> or --logfile <filename> option	(keyword: set logfile)
       is  only	 effective when	fetchmail is detached and in daemon mode. Note
       that the	logfile	must exist before fetchmail is run, you	 can  use  the
       touch(1)	command	with the filename as its sole argument to create it.
       This  option  allows  you  to redirect status messages into a specified
       logfile (follow the option with the  logfile  name).   The  logfile  is
       opened  for append, so previous messages	are not	deleted.  This is pri-
       marily useful for debugging configurations. Note	 that  fetchmail  does
       not  detect  if the logfile is rotated, the logfile is only opened once
       when fetchmail starts. You need to restart fetchmail after rotating the
       logfile and before compressing it (if applicable).

       The --syslog option (keyword: set syslog) allows	you to redirect	status
       and error messages emitted to the syslog(3) system daemon if available.
       Messages	are logged with	an id of fetchmail, the	facility LOG_MAIL, and
       priorities LOG_ERR, LOG_ALERT or	LOG_INFO.  This	option is intended for
       logging status and error	messages which indicate	the status of the dae-
       mon and the results while fetching mail from the	server(s).  Error mes-
       sages for command line options and parsing the  .fetchmailrc  file  are
       still  written to stderr, or to the specified log file.	The --nosyslog
       option turns off	use of syslog(3), assuming it  is  turned  on  in  the
       ~/.fetchmailrc file.  This option is overridden,	in certain situations,
       by --logfile (which see).

       The  -N or --nodetach option suppresses backgrounding and detachment of
       the daemon process from its control terminal.  This is useful  for  de-
       bugging	or  when  fetchmail  runs as the child of a supervisor process
       such as init(8) or Gerrit Pape's	runit(8).  Note	that this also	causes
       the logfile option to be	ignored.

       Note  that  while  running  in  daemon  mode polling a POP2 or IMAP2bis
       server, transient errors	(such as DNS failures or sendmail delivery re-
       fusals) may force the fetchall option on	for the	duration of  the  next
       polling	cycle.	This is	a robustness feature.  It means	that if	a mes-
       sage is fetched (and thus marked	seen by	the mail server) but  not  de-
       livered locally due to some transient error, it will be re-fetched dur-
       ing  the	next poll cycle.  (The IMAP logic does not delete messages un-
       til they	are delivered, so this problem does not	arise.)

       If you touch or change the ~/.fetchmailrc file while fetchmail is  run-
       ning in daemon mode, this will be detected at the beginning of the next
       poll  cycle.   When  a  changed	~/.fetchmailrc	is detected, fetchmail
       rereads it and restarts from scratch (using exec(2); no state  informa-
       tion is retained	in the new instance).  Note that if fetchmail needs to
       query  for  passwords,  of  that	if you break the ~/.fetchmailrc	file's
       syntax, the new instance	 will  softly  and  silently  vanish  away  on
       startup.

ADMINISTRATIVE OPTIONS
       The  --postmaster <name>	option (keyword: set postmaster) specifies the
       last-resort username to which multidrop mail is to be forwarded	if  no
       matching	 local	recipient can be found.	It is also used	as destination
       of undeliverable	mail if	the 'bouncemail' global	option is off and  ad-
       ditionally  for	spam-blocked mail if the 'bouncemail' global option is
       off and the 'spambounce'	global option is on. This option  defaults  to
       the user	who invoked fetchmail.	If the invoking	user is	root, then the
       default of this option is the user 'postmaster'.	 Setting postmaster to
       the  empty string causes	such mail as described above to	be discarded -
       this however is usually a bad idea.  See	also the  description  of  the
       'FETCHMAILUSER' environment variable in the ENVIRONMENT section below.

       The  --nobounce	behaves	 like  the  "set no bouncemail"	global option,
       which see.

       The --invisible option (keyword:	set invisible) tries to	make fetchmail
       invisible.  Normally, fetchmail behaves like any	other MTA would	--  it
       generates  a  Received header into each message describing its place in
       the chain of transmission, and tells the	MTA it forwards	 to  that  the
       mail  came from the machine fetchmail itself is running on.  If the in-
       visible option is on, the Received header is suppressed	and  fetchmail
       tries  to  spoof	 the MTA it forwards to	into thinking it came directly
       from the	mail server host.

       The --showdots option (keyword: set showdots) forces fetchmail to  show
       progress	 dots even if the output goes to a file	or fetchmail is	not in
       verbose mode.  Fetchmail	shows the dots by default when run  in	--ver-
       bose  mode  and	output	goes  to  console.  This  option is ignored in
       --silent	mode.

       By specifying the --tracepolls option, you can ask fetchmail to add in-
       formation to the	Received header	on the form "polling  {label}  account
       {user}",	where {label} is the account label (from the specified rcfile,
       normally	 ~/.fetchmailrc)  and  {user} is the username which is used to
       log on to the mail server. This header can be used  to  make  filtering
       email where no useful header information	is available and you want mail
       from  different	accounts  sorted into different	mailboxes (this	could,
       for example, occur if you have an account on the	same server running  a
       mailing	list,  and are subscribed to the list using that account). The
       default is not adding any such header.  In .fetchmailrc,	this is	called
       'tracepolls'.

RETRIEVAL FAILURE MODES
       The protocols fetchmail uses to talk to mail servers are	next  to  bul-
       letproof.   In  normal  operation  forwarding to	port 25, no message is
       ever deleted (or	even marked for	deletion) on the host until  the  SMTP
       listener	on the client side has acknowledged to fetchmail that the mes-
       sage  has  been	either accepted	for delivery or	rejected due to	a spam
       block.

       When forwarding to an MDA, however, there is more possibility of	error.
       Some MDAs are 'safe' and	reliably return	a nonzero status on any	deliv-
       ery error, even one due to temporary resource limits.  The  maildrop(1)
       program	is  like this; so are most programs designed as	mail transport
       agents, such as sendmail(1), including the sendmail wrapper of  Postfix
       and exim(1).  These programs give back a	reliable positive acknowledge-
       ment  and  can  be  used	with the mda option with no risk of mail loss.
       Unsafe MDAs, though, may	return 0 even on delivery  failure.   If  this
       happens,	you will lose mail.

       The normal mode of fetchmail is to try to download only 'new' messages,
       leaving	untouched  (and	 undeleted) messages you have already read di-
       rectly on the server (or	fetched	with  a	 previous  fetchmail  --keep).
       But  you	may find that messages you have	already	read on	the server are
       being fetched (and deleted) even	when you do not	specify	--all.	 There
       are several reasons this	can happen.

       One  could  be  that you	are using POP2.	 The POP2 protocol includes no
       representation of 'new' or 'old'	state in messages, so  fetchmail  must
       treat  all messages as new all the time.	 But POP2 is obsolete, so this
       is unlikely.

       A potential POP3	problem	might be servers that insert messages  in  the
       middle of mailboxes (some VMS implementations of	mail are rumored to do
       this).	The  fetchmail	code assumes that new messages are appended to
       the end of the mailbox; when this is not	true it	 may  treat  some  old
       messages	 as  new and vice versa.  Using	UIDL whilst setting fastuidl 0
       might fix this, otherwise, consider switching to	IMAP.

       Yet another POP3	problem	is that	if they	cannot make temporary files in
       the user's home directory, some POP3 servers will hand back an  undocu-
       mented response that causes fetchmail to	spuriously report "No mail".

       The  IMAP code uses the presence	or absence of the server flag \Seen to
       decide whether or not a message is new.	This is	not the	right thing to
       do, fetchmail should check the UIDVALIDITY and use UID, but it does not
       do that yet. Under Unix,	it counts on your IMAP server  to  notice  the
       BSD-style  Status  flags	set by mail user agents	and set	the \Seen flag
       from them when appropriate.  All	Unix IMAP servers we know of do	 this,
       though  it  is not specified by the IMAP	RFCs.  If you ever trip	over a
       server that does	not, the symptom will be that messages	you  have  al-
       ready  read  on	your  host  will look new to the server.  In this (un-
       likely) case, only messages you fetched with fetchmail --keep  will  be
       both undeleted and marked old.

       In  ETRN	and ODMR modes,	fetchmail does not actually retrieve messages;
       instead,	it asks	the server's SMTP listener to start a queue  flush  to
       the client via SMTP.  Therefore it sends	only undelivered messages.

SPAM FILTERING
       Many  SMTP listeners allow administrators to set	up 'spam filters' that
       block unsolicited email from specified domains.	A MAIL	FROM  or  DATA
       line that triggers this feature will elicit an SMTP response which (un-
       fortunately) varies according to	the listener.

       Newer versions of sendmail return an error code of 571.

       According  to RFC2821, the correct thing	to return in this situation is
       550 "Requested action not taken:	mailbox	unavailable" (the  draft  adds
       "[E.g.,	mailbox	 not  found, no	access,	or command rejected for	policy
       reasons].").

       Older versions of the exim MTA return 501 "Syntax error	in  parameters
       or arguments".

       The postfix MTA runs 554	as an antispam response.

       Zmailer	may  reject  code with a 500 response (followed	by an enhanced
       status code that	contains more information).

       Return codes which fetchmail treats as antispam responses and  discards
       the  message can	be set with the	'antispam' option.  This is one	of the
       only three circumstance under which fetchmail ever discards  mail  (the
       others  are the 552 and 553 errors described below, and the suppression
       of multi-dropped	messages with a	message-ID already seen).

       If fetchmail is fetching	from an	IMAP  server,  the  antispam  response
       will be detected	and the	message	rejected immediately after the headers
       have  been  fetched,  without reading the message body.	Thus, you will
       not pay for downloading spam message bodies.

       By default, the list of antispam	responses is empty.

       If the spambounce global	option is on, mail that	is spam-blocked	 trig-
       gers an RFC1892/RFC1894 bounce message informing	the originator that we
       do not accept mail from it. See also BUGS.

SMTP/ESMTP ERROR HANDLING
       Besides	the spam-blocking described above, fetchmail takes special ac-
       tions --	that may be modified by	the --softbounce option	-- on the fol-
       lowing SMTP/ESMTP error response	codes

       452 (insufficient system	storage)
	    Leave the message in the server mailbox for	later retrieval.

       552 (message exceeds fixed maximum message size)
	    Delete the message from the	server.	 Send bounce-mail to the orig-
	    inator.

       553 (invalid sending domain)
	    Delete the message from the	server.	  Do  not  even	 try  to  send
	    bounce-mail	to the originator.

       Other  errors  greater  or equal	to 500 trigger bounce mail back	to the
       originator, unless suppressed by	--softbounce. See also BUGS.

THE RUN	CONTROL	FILE
       The preferred way to set	up fetchmail is	to write a  .fetchmailrc  file
       in  your	 home directory	(you may do this directly, with	a text editor,
       or indirectly via fetchmailconf).  When there is	a conflict between the
       command-line arguments and the arguments	in this	file, the command-line
       arguments take precedence.

       To protect the security of your passwords, your ~/.fetchmailrc may  not
       normally	 have more than	0700 (u=rwx,g=,o=) permissions;	fetchmail will
       complain	and exit otherwise (this check is suppressed when --version is
       on).

       You may read the	.fetchmailrc file as a list of commands	to be executed
       when fetchmail is called	with no	arguments.

   Run Control Syntax
       Comments	begin with a '#' and extend through the	end of the line.  Oth-
       erwise the file consists	of a series of server entries or global	option
       statements in a free-format, token-oriented syntax.

       There are four kinds of tokens: grammar keywords, numbers (i.e.,	 deci-
       mal  digit  sequences), unquoted	strings, and quoted strings.  A	quoted
       string is bounded by double quotes  and	may  contain  whitespace  (and
       quoted  digits are treated as a string).	 Note that quoted strings will
       also contain line feed characters if they run across two	or more	lines,
       unless you use a	backslash to join  lines  (see	below).	  An  unquoted
       string  is  any	whitespace-delimited  token  that  is neither numeric,
       string quoted nor contains the special characters  ',',	';',  ':',  or
       '='.

       Any  amount  of	whitespace  separates tokens in	server entries,	but is
       otherwise ignored. You may use backslash	escape sequences (\n  for  LF,
       \t  for	HT,  \b	 for BS, \r for	CR, \nnn for decimal (where nnn	cannot
       start with a 0),	\0ooo for octal, and \xhh for hex) to embed non-print-
       able characters or string delimiters in strings.	 In quoted strings,  a
       backslash at the	very end of a line will	cause the backslash itself and
       the line	feed (LF or NL,	new line) character to be ignored, so that you
       can  wrap long strings. Without the backslash at	the line end, the line
       feed character would become part	of the string.

       Warning:	while these resemble C-style escape sequences,	they  are  not
       the  same.  fetchmail only supports these eight styles. C supports more
       escape sequences	that consist of	backslash (\) and a single  character,
       but  does  not support decimal codes and	does not require the leading 0
       in octal	notation.  Example: fetchmail interprets \233 the same as \xE9
       (Latin small letter e with acute), where	C would	interpret \233 as  oc-
       tal 0233	= \x9B (CSI, control sequence introducer).

       Each  server  entry  consists  of one of	the keywords 'poll' or 'skip',
       followed	by a server name, followed by server options, followed by  any
       number  of  user	 (or username) descriptions, followed by user options.
       Note: the most common cause of syntax errors  is	 mixing	 up  user  and
       server options or putting user options before the user descriptions.

       For backward compatibility, the word 'server' is	a synonym for 'poll'.

       You  can	use the	noise keywords 'and', 'with', 'has', 'wants', and 'op-
       tions' anywhere in an entry to make it resemble English.	 They are  ig-
       nored, but can make entries much	easier to read at a glance.  The punc-
       tuation characters ':', ';' and ',' are also ignored.

   Poll	versus Skip
       The  'poll' verb	tells fetchmail	to query this host when	it is run with
       no arguments.  The 'skip' verb tells fetchmail not to  poll  this  host
       unless  it  is  explicitly named	on the command line.  (The 'skip' verb
       allows you to experiment	with test entries safely,  or  easily  disable
       entries for hosts that are temporarily down.)

KEYWORD/OPTION SUMMARY
       Here are	the legal options.  Keyword suffixes enclosed in square	brack-
       ets  are	 optional.   Those corresponding to short command-line options
       are followed by '-' and the appropriate option letter.	If  option  is
       only  relevant to a single mode of operation, it	is noted as 's'	or 'm'
       for singledrop- or multidrop-mode, respectively.

       Here are	the legal global options:

       Keyword		   Opt	 Mode	Function
       --------------------------------------------------------------------
       set daemon	   -d		Set a background poll interval	in
					seconds.
       set postmaster			Give  the  name	of the last-resort
					mail recipient (default: user run-
					ning  fetchmail,  "postmaster"	if
					run by the root	user)
       set    bouncemail		Direct	error  mail  to	the sender
					(default)
       set no bouncemail		Direct error  mail  to	the  local
					postmaster  (as	 per the 'postmas-
					ter' global option above).
       set no spambounce		Do not	bounce	spam-blocked  mail
					(default).
       set    spambounce		Bounce	blocked	 spam-blocked mail
					(as per	the  'antispam'	 user  op-
					tion)  back  to	the destination	as
					indicated  by	the   'bouncemail'
					global	option.	  Warning:  Do not
					use this to bounce  spam  back	to
					the  sender  -	most  spam is sent
					with false sender address and thus
					this  option  hurts  innocent  by-
					standers.
       set no softbounce		Delete	permanently  undeliverable
					mail. It  is  recommended  to  use
					this  option  if the configuration
					has been thoroughly tested.
       set    softbounce		Keep   permanently   undeliverable
					mail  as  though a temporary error
					had occurred (default).
       set logfile	   -L		Name of	a file to append error and
					status messages	to.   Only  effec-
					tive  in daemon	mode and if fetch-
					mail  detaches.	   If	effective,
					overrides set syslog.
       set pidfile	   -p		Name of	the PID	file.
       set idfile	   -i		Name  of  the  file  to	 store UID
					lists in.
       set    syslog			Do  error  logging  through   sys-
					log(3).	 May  be overridden by set
					logfile.
       set no syslog			Turn  off  error  logging  through
					syslog(3). (default)
       set properties			String	value  that  is	ignored	by
					fetchmail (may be used	by  exten-
					sion scripts).

       Here are	the legal server options:

       Keyword		Opt   Mode   Function
       -----------------------------------------------------------------
       via			     Specify  DNS  name	of mail	server,
				     overriding	poll name
       proto[col]	-p	     Specify  protocol	(case  insensi-
				     tive):  POP2,  POP3,  IMAP,  APOP,
				     KPOP
       local[domains]	      m	     Specify domain(s) to  be  regarded
				     as	local
       port			     Specify TCP/IP service port (obso-
				     lete, use 'service' instead).
       service		-P	     Specify  service  name  (a	numeric
				     value is also allowed and	consid-
				     ered a TCP/IP port	number).
       auth[enticate]		     Set  authentication  type (default
				     'any')
       timeout		-t	     Server inactivity timeout in  sec-
				     onds (default 300)
       envelope		-E    m	     Specify   envelope-address	 header
				     name
       no envelope	      m	     Disable looking for  envelope  ad-
				     dress
       qvirtual		-Q    m	     Qmail virtual domain prefix to re-
				     move from user name
       aka		      m	     Specify  alternate	 DNS  names  of
				     mail server
       interface	-I	     specify IP	interface(s) that  must
				     be	 up  for  server  poll	to take
				     place
       monitor		-M	     Specify IP	address	to monitor  for
				     activity
       plugin			     Specify  command  through which to
				     make server connections.
       plugout			     Specify command through  which  to
				     make listener connections.
       dns		      m	     Enable  DNS  lookup  for multidrop
				     (default)
       no dns		      m	     Disable DNS lookup	for multidrop
       checkalias	      m	     Do	comparison by  IP  address  for
				     multidrop
       no checkalias	      m	     Do	 comparison  by	 name  for mul-
				     tidrop (default)
       uidl		-U	     Force  POP3  to  use   client-side
				     UIDLs (recommended)
       no uidl			     Turn  off	POP3 use of client-side
				     UIDLs (default)
       interval			     Only check	this site every	N  poll
				     cycles; N is a numeric argument.
       tracepolls		     Add  poll	tracing	 information to
				     the Received header
       principal		     Set Kerberos principal (only  use-
				     ful with IMAP and kerberos)
       esmtpname		     Set  name	for RFC2554 authentica-
				     tion to the ESMTP server.
       esmtppassword		     Set password for RFC2554 authenti-
				     cation to the ESMTP server.
       bad-header		     How to treat messages with	 a  bad
				     header. Can be reject (default) or
				     accept.

       Here are	the legal user descriptions and	options:

       Keyword		  Opt	Mode		   Function
       -------------------------------------------------------------------------------
       user[name]	  -u			   This	 is  the user description and
						   must	come first after  server  de-
						   scription   and   after   possible
						   server options,  and	 before	 user
						   options.

						   It sets the remote user name	if by
						   itself  or followed by 'there', or
						   the local user name if followed by
						   'here'.
       is					   Connect  local  and	remote	 user
						   names
       to					   Connect   local  and	 remote	 user
						   names
       pass[word]				   Specify remote account password
       ssl					   Connect to server over the  speci-
						   fied	 base  protocol	using SSL en-
						   cryption
       sslcert					   Specify file	for client side	 pub-
						   lic SSL certificate
       sslcertck				   Enable strict certificate checking
						   and	abort  connection on failure.
						   Default   only   since   fetchmail
						   v6.4.0.
       no sslcertck				   Disable  strict certificate check-
						   ing and permit connections to con-
						   tinue on failed verification. Dis-
						   couraged. Should only be used  to-
						   gether with sslfingerprint.
       sslcertfile				   Specify  file with trusted CA cer-
						   tificates
       sslcertpath				   Specify c_rehash-ed directory with
						   trusted CA certificates.
       sslfingerprint		Specify	the  ex-
				pected	  server
				certificate fin-
				ger  print  from
				an   MD5   hash.
				Fetchmail   will
				disconnect   and
				log an error  if
				it    does   not
				match.
       sslkey					   Specify file	for client side	 pri-
						   vate	SSL key
       sslproto					   Force ssl protocol for connection
       folder		  -r			   Specify remote folder to query
       smtphost		  -S			   Specify smtp	host(s)	to forward to
       fetchdomains		m		   Specify  domains  for  which	 mail
						   should be fetched
       smtpaddress	  -D			   Specify the domain to  be  put  in
						   RCPT	TO lines
       smtpname					   Specify  the	user and domain	to be
						   put in RCPT TO lines
       antispam		  -Z			   Specify what	SMTP returns are  in-
						   terpreted as	spam-policy blocks
       mda		  -m			   Specify MDA for local delivery
       bsmtp					   Specify BSMTP batch file to append
						   to
       preconnect				   Command to be executed before each
						   connection
       postconnect				   Command  to be executed after each
						   connection
       keep		  -k			   Do not delete seen  messages	 from
						   server  (for	 POP3, uidl is recom-
						   mended)
       flush		  -F			   Flush  all  seen  messages  before
						   querying (DANGEROUS)
       limitflush				   Flush  all  oversized messages be-
						   fore	querying
       fetchall		  -a			   Fetch all messages whether seen or
						   not
       rewrite					   Rewrite destination addresses  for
						   reply (default)
       stripcr					   Strip  carriage  returns from ends
						   of lines
       forcecr					   Force carriage returns at ends  of
						   lines
       pass8bits				   Force  BODY=8BITMIME	to ESMTP lis-
						   tener
       dropstatus				   Strip Status	and  X-Mozilla-Status
						   lines out of	incoming mail
       dropdelivered				   Strip  Delivered-To	lines  out of
						   incoming mail
       mimedecode				   Convert quoted-printable to	8-bit
						   in MIME messages
       idle					   Idle	 waiting for new messages af-
						   ter each poll (IMAP only)
       no keep		  -K			   Delete seen messages	 from  server
						   (default)
       no flush					   Do not flush	all seen messages be-
						   fore	querying (default)
       no fetchall				   Retrieve  only  new	messages (de-
						   fault)
       no rewrite				   Do not rewrite headers
       no stripcr				   Do not strip	carriage returns (de-
						   fault)
       no forcecr				   Do not force	carriage  returns  at
						   EOL (default)
       no pass8bits				   Do	not  force  BODY=8BITMIME  to
						   ESMTP listener (default)
       no dropstatus				   Do not drop	Status	headers	 (de-
						   fault)
       no dropdelivered				   Do  not  drop Delivered-To headers
						   (default)
       no mimedecode				   Do not convert quoted-printable to
						   8-bit in MIME messages (default)
       no idle					   Do not idle waiting for  new	 mes-
						   sages after each poll (IMAP only)
       limit		  -l			   Set message size limit
       warnings		  -w			   Set message size warning interval
       batchlimit	  -b			   Max	# messages to forward in sin-
						   gle connect
       fetchlimit	  -B			   Max # messages to fetch in  single
						   connect
       fetchsizelimit				   Max	#  message  sizes to fetch in
						   single transaction
       fastuidl					   Use binary search for first unseen
						   message (POP3 only)
       expunge		  -e			   Perform an expunge  on  every  #th
						   message (IMAP and POP3 only)
       properties				   String  value is ignored by fetch-
						   mail	(may  be  used	by  extension
						   scripts)

       All  user  options must begin with a user description (user or username
       option) and follow all server descriptions and options.

       In the .fetchmailrc file, the 'envelope'	string argument	 may  be  pre-
       ceded  by a whitespace-separated	number.	 This number, if specified, is
       the number of such headers to skip over (that is, an argument of	1  se-
       lects  the  second header of the	given type).  This is sometimes	useful
       for ignoring bogus envelope headers created by an ISP's local  delivery
       agent  or  internal  forwards (through mail inspection systems, for in-
       stance).

   Keywords Not	Corresponding To Option	Switches
       The 'folder' and	'smtphost' options (unlike their command-line  equiva-
       lents)  can  take  a  space- or comma-separated list of names following
       them.

       All options correspond to the obvious  command-line  arguments,	except
       the  following:	'via',	'interval', 'aka', 'is', 'to', 'dns'/'no dns',
       'checkalias'/'no	checkalias', 'password', 'preconnect',	'postconnect',
       'localdomains',	 'stripcr'/'no	 stripcr',   'forcecr'/'no   forcecr',
       'pass8bits'/'no	pass8bits'  'dropstatus/no  dropstatus',   'dropdeliv-
       ered/no	dropdelivered',	'mimedecode/no mimedecode', 'no	idle', and 'no
       envelope'.

       The 'via' option	is for if you want to have more	than one configuration
       pointing	at the same site.  If it is present, the string	argument  will
       be taken	as the actual DNS name of the mail server host to query.  This
       will override the argument of poll, which can then simply be a distinct
       label  for  the configuration (e.g., what you would give	on the command
       line to explicitly query	this host).

       The 'interval' option (which takes a numeric argument)  allows  you  to
       poll a server less frequently than the basic poll interval.  If you say
       'interval N' the	server this option is attached to will only be queried
       every N poll intervals.

   Singledrop versus Multidrop options
       Please  ensure  you  read  the section titled THE USE AND ABUSE OF MUL-
       TIDROP MAILBOXES	if you intend to use multidrop mode.

       The 'is'	or  'to'  keywords  associate  the  following  local  (client)
       name(s)	(or  server-name  to client-name mappings separated by =) with
       the mail	server user name in the	entry.	If an is/to list  has  '*'  as
       its  last name, unrecognized names are simply passed through. Note that
       until fetchmail version 6.3.4 inclusively, these	lists could only  con-
       tain  local  parts of user names	(fetchmail would only look at the part
       before the @ sign). fetchmail versions 6.3.5 and	newer support full ad-
       dresses on the left hand	side of	these mappings,	and they  take	prece-
       dence over any 'localdomains', 'aka', 'via' or similar mappings.

       A  single  local	name can be used to support redirecting	your mail when
       your username on	the client machine is different	from your name on  the
       mail server.  When there	is only	a single local name, mail is forwarded
       to  that	 local	username regardless of the message's Received, To, Cc,
       and Bcc headers.	 In this case, fetchmail never does DNS	lookups.

       When there is more than one local name  (or  name  mapping),  fetchmail
       looks  at  the envelope header, if configured, and otherwise at the Re-
       ceived, To, Cc, and Bcc headers of retrieved mail (this	is  'multidrop
       mode').	 It  looks  for	addresses with host name parts that match your
       poll name or your 'via',	'aka' or 'localdomains'	options,  and  usually
       also  for  host	name  parts which DNS tells it are aliases of the mail
       server.	See the	discussion of 'dns', 'checkalias', 'localdomains', and
       'aka' for details on how	matching addresses are handled.

       If fetchmail cannot match any mail server usernames or localdomain  ad-
       dresses,	 the mail will be bounced.  Normally it	will be	bounced	to the
       sender, but if the 'bouncemail' global option is	off, the mail will  go
       to the local postmaster instead.	 (see the 'postmaster' global option).
       See also	BUGS.

       The  'dns'  option  (normally  on) controls the way addresses from mul-
       tidrop mailboxes	are checked.  On, it enables logic to check each  host
       address	that  does not match an	'aka' or 'localdomains'	declaration by
       looking it up with DNS.	When a mail server username is recognized  at-
       tached  to a matching host name part, its local mapping is added	to the
       list of local recipients.

       The 'checkalias'	option (normally off) extends the lookups performed by
       the 'dns' keyword in multidrop mode, providing a	way to cope  with  re-
       mote  MTAs  that	 identify themselves using their canonical name, while
       they are	polled using an	alias.	When such a server is  polled,	checks
       to extract the envelope address fail, and fetchmail reverts to delivery
       using  the  To/Cc/Bcc  headers  (See  below 'Header versus Envelope ad-
       dresses').  Specifying this option instructs fetchmail to retrieve  all
       the  IP	addresses associated with both the poll	name and the name used
       by the remote MTA and to	do a comparison	of  the	 IP  addresses.	  This
       comes in	handy in situations where the remote server undergoes frequent
       canonical  name	changes, that would otherwise require modifications to
       the rcfile.  'checkalias' has no	effect if 'no dns' is specified	in the
       rcfile.

       The 'aka' option	is for use with	multidrop mailboxes.  It allows	you to
       pre-declare a list of DNS aliases for a server.	This is	 an  optimiza-
       tion  hack  that	 allows	you to trade space for speed.  When fetchmail,
       while processing	a multidrop mailbox, grovels through  message  headers
       looking	for  names  of	the mail server, pre-declaring common ones can
       save it from having to do DNS lookups.  Note: the names you give	as ar-
       guments to 'aka'	are matched as suffixes	-- if you specify  (say)  'aka
       netaxs.com',  this  will	match not just a host name netaxs.com, but any
       host name that ends with	'.netaxs.com'; such as	(say)  pop3.netaxs.com
       and mail.netaxs.com.

       The 'localdomains' option allows	you to declare a list of domains which
       fetchmail  should  consider  local.   When fetchmail is parsing address
       lines in	multidrop modes, and a trailing	segment	of a host name matches
       a declared local	domain,	that address is	passed through to the listener
       or MDA unaltered	(local-name mappings are not applied).

       If you are using	'localdomains',	you may	also need to specify 'no enve-
       lope', which disables fetchmail's normal	attempt	to deduce an  envelope
       address	from  the  Received  line  or X-Envelope-To header or whatever
       header has been previously set by 'envelope'.  If you set 'no envelope'
       in the defaults entry it	is possible to undo that in individual entries
       by using	'envelope <string>'.  As a special case, 'envelope "Received"'
       restores	the default parsing of Received	lines.

       The password option requires a string argument, which is	 the  password
       to be used with the entry's server.

       The  'preconnect'  keyword  allows you to specify a shell command to be
       executed	just before each time fetchmail	establishes a mail server con-
       nection.	 This may be useful if you are attempting to set up secure POP
       connections with	the aid	of ssh(1).  If the command returns  a  nonzero
       status, the poll	of that	mail server will be aborted.

       Similarly,  the 'postconnect' keyword similarly allows you to specify a
       shell command to	be executed just after each time a mail	server connec-
       tion is taken down.

       The 'forcecr' option controls whether lines terminated by LF  only  are
       given CRLF termination before forwarding.  Strictly speaking RFC821 re-
       quires  this,  but  few	MTAs enforce the requirement so	this option is
       normally	off (only one such MTA,	qmail, is in significant use  at  time
       of writing).

       The 'stripcr' option controls whether carriage returns are stripped out
       of retrieved mail before	it is forwarded.  It is	normally not necessary
       to  set	this,  because it defaults to 'on' (CR stripping enabled) when
       there is	an MDA declared	but 'off' (CR stripping	 disabled)  when  for-
       warding is via SMTP.  If	'stripcr' and 'forcecr'	are both on, 'stripcr'
       will override.

       The 'pass8bits' option exists to	cope with Microsoft mail programs that
       stupidly	 slap a	"Content-Transfer-Encoding: 7bit" on everything.  With
       this option off (the default) and such a	header present,	fetchmail  de-
       clares BODY=7BIT	to an ESMTP-capable listener; this causes problems for
       messages	 actually  using 8-bit ISO or KOI-8 character sets, which will
       be garbled by having the	high bits  of  all  characters	stripped.   If
       'pass8bits'  is on, fetchmail is	forced to declare BODY=8BITMIME	to any
       ESMTP-capable listener.	If the listener	is 8-bit-clean (as all the ma-
       jor ones	now are) the right thing will probably result.

       The 'dropstatus'	option controls	whether	nonempty Status	and X-Mozilla-
       Status lines are	retained in fetched mail (the default)	or  discarded.
       Retaining  them	allows	your  MUA  to  see what	messages (if any) were
       marked seen on the server.  On the other	hand, it can confuse some new-
       mail notifiers, which assume that anything with a Status	line in	it has
       been seen.  (Note: the empty Status lines inserted by  some  buggy  POP
       servers are unconditionally discarded.)

       The  'dropdelivered'  option controls whether Delivered-To headers will
       be kept in fetched mail (the default) or	discarded. These  headers  are
       added  by  qmail	 and Postfix mail servers in order to avoid mail loops
       but may get in your way if you try to "mirror" a	mail server within the
       same domain. Use	with caution.

       The 'mimedecode'	 option	 controls  whether  MIME  messages  using  the
       quoted-printable	 encoding  are automatically converted into pure 8-bit
       data. If	you are	delivering mail	to an ESMTP-capable, 8-bit-clean  lis-
       tener  (that  includes  all of the major	MTAs like sendmail), then this
       will automatically convert quoted-printable message  headers  and  data
       into  8-bit  data, making it easier to understand when reading mail. If
       your e-mail programs know how to	deal with MIME messages, then this op-
       tion is not needed.  The	mimedecode option is off by  default,  because
       doing  RFC2047 conversion on headers throws away	character-set informa-
       tion and	can lead to bad	results	if the encoding	of the headers differs
       from the	body encoding.

       The 'idle' option is intended to	be used	with IMAP  servers  supporting
       the  RFC2177  IDLE command extension, but does not strictly require it.
       If it is	enabled, and fetchmail detects that IDLE is supported, an IDLE
       will be issued at the end of each poll.	This will tell the IMAP	server
       to hold the connection open and notify the  client  when	 new  mail  is
       available.  If IDLE is not supported, fetchmail will simulate it	by pe-
       riodically  issuing  NOOP.  If you need to poll a link frequently, IDLE
       can save	bandwidth by eliminating TCP/IP	connects and LOGIN/LOGOUT  se-
       quences.	 On  the other hand, an	IDLE connection	will eat almost	all of
       your fetchmail's	time, because it will never drop  the  connection  and
       allow  other  polls  to occur unless the	server times out the IDLE.  It
       also does not work with multiple	folders; only the  first  folder  will
       ever be polled.

       The  'properties'  option is an extension mechanism.  It	takes a	string
       argument, which is ignored by fetchmail itself.	 The  string  argument
       may  be	used  to store configuration information for scripts which re-
       quire it.  In particular, the output of '--configdump' option will make
       properties associated with a user entry readily available to  a	Python
       script.

   Miscellaneous Run Control Options
       The  words  'here'  and	'there'	have useful English-like significance.
       Normally	'user eric is esr' would mean that mail	for  the  remote  user
       'eric'  is  to  be delivered to 'esr', but you can make this clearer by
       saying 'user eric there is esr here', or	reverse	it by saying 'user esr
       here is eric there'

       Legal protocol identifiers for use with the 'protocol' keyword are:

	   auto	(or AUTO) (legacy, to be removed from future release)
	   pop2	(or POP2) (legacy, to be removed from future release)
	   pop3	(or POP3)
	   sdps	(or SDPS)
	   imap	(or IMAP)
	   apop	(or APOP)
	   kpop	(or KPOP)

       Legal authentication types are  'any',  'password',  'kerberos',	 'ker-
       beros_v4',  'kerberos_v5'  and 'gssapi',	'cram-md5', 'otp', 'msn' (only
       for POP3), 'ntlm', 'ssh', 'external' (only IMAP).  The 'password'  type
       specifies  authentication  by  normal  transmission  of a password (the
       password	may be plain text or subject to	 protocol-specific  encryption
       as  in  CRAM-MD5);  'kerberos' tells fetchmail to try to	get a Kerberos
       ticket at the start of each query instead, and send an arbitrary	string
       as the password;	and 'gssapi' tells fetchmail to	use GSSAPI authentica-
       tion.  See the description of the 'auth'	keyword	for more.

       Specifying 'kpop' sets POP3 protocol over port 1109  with  Kerberos  V4
       authentication.	These defaults may be overridden by later options.

       There  are  some	 global	option statements: 'set	logfile' followed by a
       string sets the same global specified  by  --logfile.   A  command-line
       --logfile option	will override this. Note that --logfile	is only	effec-
       tive if fetchmail detaches itself from the terminal and the logfile al-
       ready exists before fetchmail is	run, and it overrides --syslog in this
       case.   Also,  'set  daemon'  sets  the poll interval as	--daemon does.
       This can	be overridden by a command-line	--daemon option; in particular
       --daemon	0 can be used to force foreground operation. The 'set postmas-
       ter' statement sets the address to which	 multidrop  mail  defaults  if
       there  are  no local matches.  Finally, 'set syslog' sends log messages
       to syslogd(8).

DEBUGGING FETCHMAIL
   Fetchmail crashing
       There are various ways in that fetchmail	may "crash", i.	e. stop	opera-
       tion suddenly and unexpectedly. A "crash" usually refers	 to  an	 error
       condition  that	the  software  did  not	handle by itself. A well-known
       failure mode is the "segmentation fault"	or "signal 11" or "SIGSEGV" or
       just "segfault" for short. These	can be caused by hardware or by	 soft-
       ware  problems.	Software-induced  segfaults  can usually be reproduced
       easily and in the same place, whereas hardware-induced segfaults	can go
       away if the computer is rebooted, or powered off	for a few  hours,  and
       can  happen  in	random locations even if you use the software the same
       way.

       For solving hardware-induced segfaults, find the	faulty	component  and
       repair  or replace it.  The Sig11 FAQ <https://www.bitwizard.nl/sig11/>
       may help	you with details.

       For solving software-induced  segfaults,	 the  developers  may  need  a
       "stack backtrace".

   Enabling fetchmail core dumps
       By  default,  fetchmail	suppresses  core  dumps	as these might contain
       passwords and other  sensitive  information.  For  debugging  fetchmail
       crashes,	 obtaining  a  "stack backtrace" from a	core dump is often the
       quickest	way to solve the problem, and when posting your	problem	 on  a
       mailing list, the developers may	ask you	for a "backtrace".

       1.  To  get  useful backtraces, fetchmail needs to be installed without
       getting stripped	of its compilation symbols.  Unfortunately,  most  bi-
       nary packages that are installed	are stripped, and core files from sym-
       bol-stripped  programs  are  worthless.	So  you	 may need to recompile
       fetchmail. On many systems, you can type

	       file `which fetchmail`

       to find out if fetchmail	was symbol-stripped or not. If yours  was  un-
       stripped,  fine,	proceed, if it was stripped, you need to recompile the
       source code first. You do not usually need to install fetchmail in  or-
       der to debug it.

       2.  The	shell  environment  that starts	fetchmail needs	to enable core
       dumps. The key is the "maximum core (file) size"	that  can  usually  be
       configured with a tool named "limit" or "ulimit". See the documentation
       for  your shell for details. In the popular bash	shell, "ulimit -Sc un-
       limited"	will allow the core dump.

       3. You need to tell fetchmail, too, to allow core dumps.	 To  do	 this,
       run  fetchmail with the -d0 -v options.	It is often easier to also add
       --nosyslog -N as	well.

       Finally,	you need to reproduce the crash. You can just start  fetchmail
       from  the directory where you compiled it by typing ./fetchmail,	so the
       complete	command	line will start	with ./fetchmail -Nvd0 --nosyslog  and
       perhaps list your other options.

       After the crash,	run your debugger to obtain the	core dump.  The	debug-
       ger  will  often	 be GNU	GDB, you can then type (adjust paths as	neces-
       sary) gdb ./fetchmail fetchmail.core and	then, after GDB	has started up
       and read	all its	files, type backtrace full, save the  output  (copy  &
       paste  will  do,	 the  backtrace	will be	read by	a human) and then type
       quit to leave gdb.  Note: on some systems, the core files have  differ-
       ent  names, they	might contain a	number instead of the program name, or
       number and name,	but it will usually have "core"	as part	of their name.

INTERACTION WITH RFC 822
       When trying to determine	the originating	address	of a  message,	fetch-
       mail looks through headers in the following order:

	       Return-Path:
	       Resent-Sender: (ignored if it does not contain an @ or !)
	       Sender: (ignored	if it does not contain an @ or !)
	       Resent-From:
	       From:
	       Reply-To:
	       Apparently-From:

       The  originating	 address is used for logging, and to set the MAIL FROM
       address when forwarding to SMTP.	 This order is intended	to cope	grace-
       fully with receiving mailing list messages in multidrop mode.  The  in-
       tent is that if a local address does not	exist, the bounce message will
       not be returned blindly to the author or	to the list itself, but	rather
       to the list manager (which is less annoying).

       In multidrop mode, destination headers are processed as follows:	First,
       fetchmail  looks	 for  the header specified by the 'envelope' option in
       order to	determine the local recipient address.	If  the	 mail  is  ad-
       dressed	to more	than one recipient, the	Received line will not contain
       any information regarding recipient addresses.

       Then fetchmail looks for	the Resent-To:,	 Resent-Cc:,  and  Resent-Bcc:
       lines.	If  they  exist,  they should contain the final	recipients and
       have precedence over their To:/Cc:/Bcc: counterparts.  If the  Resent-*
       lines  do  not  exist,  the To:,	Cc:, Bcc: and Apparently-To: lines are
       looked for. (The	presence of a Resent-To: is taken to  imply  that  the
       person  referred	 by  the To: address has already received the original
       copy of the mail.)

CONFIGURATION EXAMPLES
       Note that although there	are password declarations in a	good  many  of
       the  examples below, this is mainly for illustrative purposes.  We rec-
       ommend stashing account/password	pairs in your $HOME/.netrc file, where
       they can	be used	not just by fetchmail but by  ftp(1)  and  other  pro-
       grams.

       The basic format	is:

	      poll  SERVERNAME	protocol PROTOCOL username NAME	password PASS-
	      WORD

       Example:

	      poll pop.provider.net protocol pop3 username "jsmith" password "secret1"

       Or, using some abbreviations:

	      poll pop.provider.net proto pop3 user "jsmith" password "secret1"

       Multiple	servers	may be listed:

	      poll pop.provider.net proto pop3 user "jsmith" pass "secret1"
	      poll other.provider.net proto pop2 user "John.Smith" pass	"My^Hat"

       Here is the same	version	with more whitespace and some noise words:

	      poll pop.provider.net proto pop3
		   user	"jsmith", with password	secret1, is "jsmith" here;
	      poll other.provider.net proto pop2:
		   user	"John.Smith", with password "My^Hat", is "John.Smith" here;

       If you need to include whitespace in a parameter	string	or  start  the
       latter with a number, enclose the string	in double quotes.  Thus:

	      poll mail.provider.net with proto	pop3:
		   user	"jsmith" there has password "4u	but u cannot krak this"
		   is jws here and wants mda "/bin/mail"

       You  may	 have an initial server	description headed by the keyword 'de-
       faults' instead of 'poll' followed by a name.  Such a record is	inter-
       preted as defaults for all queries to use. It may be overwritten	by in-
       dividual	server descriptions.  So, you could write:

	      defaults proto pop3
		   user	"jsmith"
	      poll pop.provider.net
		   pass	"secret1"
	      poll mail.provider.net
		   user	"jjsmith" there	has password "secret2"

       It  is  possible	 to specify more than one user per server.  The	'user'
       keyword leads off a user	description, and every user specification in a
       multi-user entry	must include it.  Here is an example:

	      poll pop.provider.net proto pop3 port 3111
		   user	"jsmith" with pass "secret1" is	"smith"	here
		   user	jones with pass	"secret2" is "jjones" here keep

       This associates the local username 'smith'  with	 the  pop.provider.net
       username	  'jsmith'   and   the	 local	 username  'jjones'  with  the
       pop.provider.net	username 'jones'.  Mail	for 'jones'  is	 kept  on  the
       server after download.

       Here  is	 what a	simple retrieval configuration for a multidrop mailbox
       looks like:

	      poll pop.provider.net:
		   user	maildrop with pass secret1 to golux 'hurkle'='happy' snark here

       This says that the mailbox of account 'maildrop'	on  the	 server	 is  a
       multidrop  box, and that	messages in it should be parsed	for the	server
       user names 'golux', 'hurkle', and 'snark'.  It further  specifies  that
       'golux'	and 'snark' have the same name on the client as	on the server,
       but mail	for server user	'hurkle' should	be delivered  to  client  user
       'happy'.

       Note  that  fetchmail, until version 6.3.4, did NOT allow full user@do-
       main specifications here, these would never match.  Fetchmail 6.3.5 and
       newer support user@domain specifications	on the	left-hand  side	 of  a
       user mapping.

       Here is an example of another kind of multidrop connection:

	      poll pop.provider.net localdomains loonytoons.org	toons.org
		   envelope X-Envelope-To
		   user	maildrop with pass secret1 to *	here

       This  also says that the	mailbox	of account 'maildrop' on the server is
       a multidrop box.	 It tells fetchmail that any  address  in  the	loony-
       toons.org  or  toons.org	 domains  (including sub-domain	addresses like
       'joe@daffy.loonytoons.org') should be passed through to the local  SMTP
       listener	 without  modification.	  Be  careful  of mail loops if	you do
       this!

       Here is an example configuration	using ssh and the plugin option.   The
       queries	are  made  directly  on	the stdin and stdout of	imapd via ssh.
       Note that in this setup,	IMAP authentication can	be skipped.

	      poll mailhost.net	with proto imap:
		   plugin "ssh %h /usr/sbin/imapd" auth	ssh;
		   user	esr is esr here

THE USE	AND ABUSE OF MULTIDROP MAILBOXES
       Use the multiple-local-recipients feature with caution -- it can	 bite.
       All multidrop features are ineffective in ETRN and ODMR modes.

       Also, note that in multidrop mode duplicate mails may be	suppressed.  A
       piece of	mail is	considered duplicate if	it does	not have a discernible
       envelope	 recipient address, has	the same header	as the message immedi-
       ately preceding and more	than one addressee.  Such runs of messages may
       be generated when copies	of a message addressed to multiple  users  are
       delivered  to  a	multidrop box. (To be precise, fetchmail 6.2.5 through
       6.4.X use an MD5	hash of	the raw	message	 header,  and  only  fetchmail
       6.4.16+	document  this properly.  Fetchmail 5.0.8 (1999-09-14) through
       6.2.4 used only the Message-ID header.  5.0.7 and older	did  not  sup-
       press duplicates.)

       Note  that  this	 duplication killer code checking the entire header is
       very restrictive	and may	not suppress many duplicates in	practice - for
       instance, if some X-Original-To or Delivered-To header  differs.	  This
       is intentional and correct in such situations: wherever envelope	infor-
       mation is available, it should be used for reliable delivery of mailing
       list and	blind carbon copy (Bcc)	messages. See the subsection Duplicate
       suppression below for suggestions.

   Header versus Envelope addresses
       The fundamental problem is that by having your mail server toss several
       peoples'	mail in	a single maildrop box, you may have thrown away	poten-
       tially  vital information about who each	piece of mail was actually ad-
       dressed to (the 'envelope address', as opposed to the header  addresses
       in the RFC822 To/Cc headers - the Bcc is	not available at the receiving
       end).   This  'envelope	address'  is  the address you need in order to
       reroute mail properly.

       Sometimes fetchmail can deduce  the  envelope  address.	 If  the  mail
       server MTA is sendmail and the item of mail had just one	recipient, the
       MTA  will  have	written	 a 'by/for' clause that	gives the envelope ad-
       dressee into its	Received header. But this does not work	 reliably  for
       other  MTAs,  nor  if  there  is	 more than one recipient.  By default,
       fetchmail looks for envelope addresses in these lines; you can  restore
       this default with -E "Received" or 'envelope Received'.

       As a better alternative,	some SMTP listeners and/or mail	servers	insert
       a  header  in each message containing a copy of the envelope addresses.
       This header (when it exists) is often  'X-Original-To',	'Delivered-To'
       or  'X-Envelope-To'.   Fetchmail's assumption about this	can be changed
       with the	-E or 'envelope' option.  Note that writing an envelope	header
       of this kind exposes the	names of recipients (including blind-copy  re-
       cipients)  to all receivers of the messages, so the upstream must store
       one copy	of the message per recipient to	avoid becoming a privacy prob-
       lem.

       Postfix,	since version 2.0, writes an X-Original-To: header which  con-
       tains a copy of the envelope as it was received.

       Qmail and Postfix generally write a 'Delivered-To' header upon deliver-
       ing  the	 message  to  the  mail	 spool and use it to avoid mail	loops.
       Qmail virtual domains however will prefix the user name with  a	string
       that  normally matches the user's domain. To remove this	prefix you can
       use the -Q or 'qvirtual'	option.

       Sometimes, unfortunately, neither of these methods works.  That is  the
       point  when you should contact your ISP and ask them to provide such an
       envelope	header,	and you	should not use multidrop  in  this  situation.
       When  they  all fail, fetchmail must fall back on the contents of To/Cc
       headers (Bcc headers are	not available -	see below) to try to determine
       recipient addressees -- and these are unreliable.  In particular, mail-
       ing-list	software often ships mail with only the	list broadcast address
       in the To: header.

       Note that a future version of fetchmail may remove To/Cc	parsing!

       When fetchmail cannot deduce a recipient	address	that is	local, and the
       intended	recipient address was anyone other than	 fetchmail's  invoking
       user,  mail  will  get  lost.  This is what makes the multidrop feature
       risky without proper envelope information.

       A related problem is that when you blind-copy a mail message,  the  Bcc
       information is carried only as envelope address (it is removed from the
       headers	by  the	 sending  mail server, so fetchmail can	see it only if
       there is	an X-Envelope-To header).  Thus, blind-copying to someone  who
       gets  mail  over	 a  fetchmail multidrop	link will fail unless the mail
       server host routinely writes X-Envelope-To or an	equivalent header into
       messages	in your	maildrop.

       In conclusion, mailing lists and	Bcc'd mail can only work if the	server
       you are fetching	from

       (1)    stores one copy of the message per recipient in your domain and

       (2)    records the envelope information in a special  header  (X-Origi-
	      nal-To, Delivered-To, X-Envelope-To).

   Good	Ways To	Use Multidrop Mailboxes
       Multiple	 local names can be used to administer a mailing list from the
       client side of a	fetchmail collection.  Suppose your name is 'esr', and
       you want	to both	pick up	your own mail  and  maintain  a	 mailing  list
       called  (say)  "fetchmail-friends", and you want	to keep	the alias list
       on your client machine.

       On your server, you can alias 'fetchmail-friends' to  'esr';  then,  in
       your .fetchmailrc, declare 'to esr fetchmail-friends here'.  Then, when
       mail including 'fetchmail-friends' as a local address gets fetched, the
       list name will be appended to the list of recipients your SMTP listener
       sees.   Therefore  it will undergo alias	expansion locally.  Be sure to
       include 'esr' in	the local alias	expansion of fetchmail-friends,	or you
       will never see mail sent	only to	the list.  Also	be sure	that your lis-
       tener has the "me-too" option set (sendmail's -oXm command-line	option
       or  OXm	declaration) so	your name is not removed from alias expansions
       in messages you send.

       This trick is not without its problems, however.	 You will begin	to see
       this when a message comes in that is addressed only to a	 mailing  list
       you  do not have	declared as a local name.  Each	such message will fea-
       ture an 'X-Fetchmail-Warning' header which is generated because	fetch-
       mail  cannot  find a valid local	name in	the recipient addresses.  Such
       messages	default	(as was	described above) to being sent	to  the	 local
       user running fetchmail, but the program has no way to know that this is
       actually	the right thing.

   Bad Ways To Abuse Multidrop Mailboxes
       Multidrop mailboxes and fetchmail serving multiple users	in daemon mode
       do not mix.  The	problem, again,	is mail	from mailing lists, which typ-
       ically  does  not  have an individual recipient address on it.	Unless
       fetchmail can deduce an envelope	address, such mail will	only go	to the
       account running fetchmail (probably root).   Also,  blind-copied	 users
       are very	likely never to	see their mail at all.

       If you are tempted to use fetchmail to retrieve mail for	multiple users
       from  a	single	mail drop via POP or IMAP, think again (and reread the
       section on header and envelope addresses	above).	 It would  be  smarter
       to just let the mail sit	in the mail server's queue and use fetchmail's
       ETRN  or	ODMR modes to trigger SMTP sends periodically (of course, this
       means you have to poll more frequently than the	mail  server's	expiry
       period).	 If you	cannot arrange this, try setting up a UUCP feed.

       If  you	absolutely must	use multidrop for this purpose,	make sure your
       mail server writes an envelope-address header that fetchmail  can  see.
       Otherwise you will lose mail and	it will	come back to haunt you.

   Speeding Up Multidrop Checking
       Normally, when multiple users are declared fetchmail extracts recipient
       addresses  as described above and checks	each host part with DNS	to see
       if it is	an alias of the	mail server.  If so,  the  name	 mappings  de-
       scribed	in the "to ... here" declaration are done and the mail locally
       delivered.

       This is a convenient but	also slow method.  To speed it up, pre-declare
       mail server aliases with	'aka'; these are checked  before  DNS  lookups
       are done.  If you are certain your aka list contains all	DNS aliases of
       the mail	server (and all	MX names pointing at it	- note this may	change
       in  a  future version) you can declare 'no dns' to suppress DNS lookups
       entirely	and only match against the aka list.

   Duplicate suppression on multidrop
       If fetchmail's duplicate	suppression code does not  kick	 in  for  your
       multidrop  mail	account, other options is using	sieve, or for instance
       Courier's maildrop package (and in particular,  its  reformail  program
       with  the  -D  option) as the delivery agent (either from fetchmail, or
       from your local mail server that	fetchmail injects into).

SOCKS
       Support for socks4/5 is a compile time configuration option. Once  com-
       piled  in, fetchmail will always	use the	socks libraries	and configura-
       tion on your system, there are no run-time switches in fetchmail	-  but
       you  can	 still configure SOCKS:	you can	specify	which SOCKS configura-
       tion file is used in the	SOCKS_CONF environment variable.

       For instance, if	you wanted to bypass the SOCKS	proxy  altogether  and
       have    fetchmail    connect    directly,    you	   could   just	  pass
       SOCKS_CONF=/dev/null in the environment,	for example  (add  your	 usual
       command line options - if any - to the end of this line):

       env SOCKS_CONF=/dev/null	fetchmail

EXIT CODES
       To  facilitate  the  use	 of fetchmail in shell scripts,	an exit	status
       code is returned	to give	an indication of what occurred during a	 given
       connection.

       The exit	codes returned by fetchmail are	as follows:

       0      One  or more messages were successfully retrieved	(or, if	the -c
	      option was selected, were	found waiting but not retrieved).

       1      There was	no mail	awaiting retrieval.  (There may	have been  old
	      mail still on the	server but not selected	for retrieval.)	If you
	      do  not  want  "no mail" to be an	error condition	(for instance,
	      for cron jobs), use a POSIX-compliant shell and add

	      || [ $? -eq 1 ]

	      to the end of the	fetchmail command line,	note that this	leaves
	      0	 untouched,  maps  1  to 0, and	maps all other codes to	1. See
	      also item	#C8 in the FAQ.

       2      An error was encountered when attempting to open a socket	to re-
	      trieve mail.  If you do not know what a socket is, do not	 worry
	      about  it	 -- just treat this as an 'unrecoverable error'.  This
	      error can	also be	because	a protocol fetchmail wants to  use  is
	      not listed in /etc/services.

       3      The  user	authentication step failed.  This usually means	that a
	      bad user-id, password, or	APOP id	was specified.	Or it may mean
	      that you tried to	run fetchmail under circumstances where	it did
	      not have standard	input attached to a  terminal  and  could  not
	      prompt for a missing password.

       4      Some sort	of fatal protocol error	was detected.

       5      There  was  a  syntax  error in the arguments to fetchmail, or a
	      pre- or post-connect command failed.

       6      The run control file had bad permissions.

       7      There was	an error condition reported by the server.   Can  also
	      fire if fetchmail	timed out while	waiting	for the	server.

       8      Client-side  exclusion error.  This means	fetchmail either found
	      another copy of itself already running, or failed	in such	a  way
	      that it is not sure whether another copy is running.

       9      The user authentication step failed because the server responded
	      "lock  busy".  Try again after a brief pause!  This error	is not
	      implemented for all protocols, nor for all servers.  If not  im-
	      plemented	 for  your  server,  "3" will be returned instead, see
	      above.  May be returned when talking to qpopper or other servers
	      that can respond with "lock busy"	or some	similar	text  contain-
	      ing the word "lock".

       10     The fetchmail run	failed while trying to do an SMTP port open or
	      transaction.

       11     Fatal  DNS error.	 Fetchmail encountered an error	while perform-
	      ing a DNS	lookup at startup and could not	proceed.

       12     BSMTP batch file could not be opened.

       13     Poll terminated by a fetch limit (see the	--fetchlimit option).

       14     Server busy indication.

       23     Internal error.  You should see a	message	on standard error with
	      details.

       24 - 26,	28, 29
	      These are	internal codes and should not appear externally.

       When fetchmail queries more than	one host, return status	is  0  if  any
       query  successfully retrieved mail. Otherwise the returned error	status
       is that of the last host	queried.

FILES
       ~/.fetchmailrc, $HOME/.fetchmailrc, $HOME_ETC/.fetchmailrc, $FETCHMAIL-
       HOME/fetchmailrc
	    default run	control	file (location can be overridden with environ-
	    ment variables)

       ~/.fetchids, $HOME/.fetchids, $HOME_ETC/.fetchids, $FETCHMAIL-
       HOME/.fetchids
	    default location of	file recording	last  message  UIDs  seen  per
	    host.  (location can be overridden with environment	variables)

       ~/.fetchmail.pid, $HOME/.fetchmail.pid, $HOME_ETC/.fetchmail.pid,
       $FETCHMAILHOME/fetchmail.pid
	    default  location  of  lock	 file (sometimes called	pidfile	or PID
	    file, see option pidfile) to help prevent  concurrent  runs	 (non-
	    root  mode).   (location  can be overridden	with environment vari-
	    ables)

       ~/.netrc, $HOME/.netrc, $HOME_ETC/.netrc
	    your FTP run control file, which (if present) will be searched for
	    passwords as a last	resort before prompting	for one	interactively.
	    (location can be overridden	with environment variables)

       /var/run/fetchmail.pid
	    lock file (pidfile)	to help	prevent	concurrent  runs  (root	 mode,
	    Linux systems).

       /etc/fetchmail.pid
	    lock  file	(pidfile)  to help prevent concurrent runs (root mode,
	    systems without /var/run).

ENVIRONMENT
       Fetchmail's behavior can	be altered by providing	 it  with  environment
       variables.   Some  may  alter the operation of libraries	that fetchmail
       links against, for instance, OpenSSL.  Note that	in  daemon  mode,  you
       will  need to quit the background daemon	process	and start a new	fetch-
       mail daemon for environment changes to take effect.

       FETCHMAILHOME
	      If this environment variable is set to a valid and existing  di-
	      rectory  name,  fetchmail	 will  read $FETCHMAILHOME/fetchmailrc
	      (the dot is  missing  in	this  case),  $FETCHMAILHOME/.fetchids
	      (keeping its dot)	and $FETCHMAILHOME/fetchmail.pid (without dot)
	      rather  than from	the user's home	directory.  The	.netrc file is
	      always looked for	in the	invoking  user's  home	directory  (or
	      $HOME_ETC) regardless of FETCHMAILHOME's setting.

       FETCHMAILUSER
	      If  this	environment variable is	set, it	is used	as the name of
	      the calling user (default	local name) for	purposes such as mail-
	      ing error	notifications.	Otherwise, if either  the  LOGNAME  or
	      USER  variable  is  correctly  set  (e.g., the corresponding UID
	      matches the session user ID) then	that name is used as  the  de-
	      fault  local  name.   Otherwise  getpwuid(3) must	be able	to re-
	      trieve a password	entry for the session ID (this elaborate logic
	      is designed to handle the	case of	multiple  names	 per  user  ID
	      gracefully).

       FETCHMAIL_DISABLE_CBC_IV_COUNTERMEASURE
	      (since  v6.3.22):	 If  this  environment variable	is set and not
	      empty, fetchmail will disable a countermeasure  against  an  SSL
	      CBC  IV  attack (by setting SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS).
	      This is a	security risk, but may be necessary for	connecting  to
	      certain  non-standards-conforming	servers.  See fetchmail's NEWS
	      file and fetchmail-SA-2012-01.txt	for details.   Earlier	fetch-
	      mail  versions (v6.3.21 and older) used to disable this counter-
	      measure, but v6.3.22 no longer does that as a safety precaution.

       FETCHMAIL_POP3_FORCE_RETR
	      (since v6.3.9): If this environment variable is defined  at  all
	      (even  if	 empty), fetchmail will	forgo the POP3 TOP command and
	      always use RETR. This can	be used	as a workaround	when TOP  does
	      not work properly.

       FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS
	      (since  v6.3.17):	 If  this  environment variable	is set and not
	      empty, fetchmail will always load	the default X.509 trusted cer-
	      tificate	locations  for	SSL/TLS	 CA  certificates,   even   if
	      --sslcertfile and	--sslcertpath are given.  The latter locations
	      take precedence over the system default locations.  This is use-
	      ful in case there	are broken certificates	in the system directo-
	      ries  and	the user has no	administrator privileges to remedy the
	      problem.

       FETCHMAIL_WOLFSSL_DEBUG
	      (since v6.4.25): If fetchmail is compiled	and linked with	 wolf-
	      SSL, if wolfSSL was built	with --enable-debug, and if this envi-
	      ronment variable is set and not empty, then enable wolfSSL's de-
	      bug mode.	This will emit huge amounts of debug output to stderr.

       HOME   (documented  since  6.4.1): This variable	is normally set	to the
	      user's home directory. If	it is set  to  a  different  directory
	      than what	is in the password database, HOME takes	precedence.

       HOME_ETC
	      (documentation  corrected	 to  match  behaviour  of  code	 since
	      6.4.1): If the HOME_ETC variable is set, it will override	fetch-
	      mail's idea of $HOME, i. e. fetchmail  will  read	 .fetchmailrc,
	      .fetchids,  .fetchmail.pid  and .netrc from $HOME_ETC instead of
	      $HOME (or	if HOME	is also	unset, from the	passwd file's home di-
	      rectory location).

	      If HOME_ETC and FETCHMAILHOME are	both set, FETCHMAILHOME	 takes
	      precedence and HOME_ETC will be ignored.

       SOCKS_CONF
	      (only  if	SOCKS support is compiled in) this variable is used by
	      the socks	library	to find	out which configuration	file it	should
	      read. Set	this to	/dev/null to bypass the	SOCKS proxy.

       SSL_CERT_DIR
	      (with  truly  OpenSSL  1.1.1  compatible	 library):   overrides
	      OpenSSL's	 idea  of  the	default	trust directory	or path	(which
	      contains individual certificate files and	hashed symlinks),  see
	      the SSL_CTX_set_default_verify_paths(3) manual page for details,
	      it  may be in the	openssl	development package.  If using another
	      library's	OpenSSL	compatibility interface, this  may  not	 work.
	      Since  this  variable only specifies a default value, the	option
	      --sslcertpath takes precedence if	given.

       SSL_CERT_FILE
	      (with  truly  OpenSSL  1.1.1  compatible	 library):   overrides
	      OpenSSL's	 idea  of  the	default	 trust certificate bundle file
	      (which contains a	concatenation of  base64-encoded  certificates
	      in PEM format), see the SSL_CTX_set_default_verify_paths(3) man-
	      ual page for details, it may be in the openssl development pack-
	      age.   If	 using	another	library's OpenSSL compatibility	inter-
	      face, this may not work.	Since this variable only  specifies  a
	      default  value,  the  option  --sslcertfile  takes precedence if
	      given.

SIGNALS
       If a fetchmail daemon is	running	as root, SIGUSR1 wakes it up from  its
       sleep  phase and	forces a poll of all non-skipped servers. For compati-
       bility reasons, SIGHUP can also be used in 6.3.X	but may	not be	avail-
       able in future fetchmail	versions.

       If fetchmail is running in daemon mode as non-root, use SIGUSR1 to wake
       it  (this  is  so SIGHUP	due to logout can retain the default action of
       killing it).

       Running fetchmail in foreground while a background fetchmail is running
       will do whichever of these is appropriate to wake it up.

BUGS, LIMITATIONS, AND KNOWN PROBLEMS
       Please check the	NEWS file that shipped with fetchmail for  more	 known
       bugs than those listed here.

       Fetchmail  cannot  handle  user	names  that contain blanks after a "@"
       character, for instance "demonstr@ti on". These are rather uncommon and
       only hurt when using UID-based --keep setups, so	the 6.X.Y versions  of
       fetchmail will not be fixed.

       Fetchmail cannot	handle configurations where you	have multiple accounts
       that  use the same server name and the same login. Any user@server com-
       bination	must be	unique.

       The assumptions that the	DNS and	in particular the  checkalias  options
       make  are  not  often sustainable. For instance,	it has become uncommon
       for an MX server	to be a	POP3 or	IMAP server at the same	 time.	There-
       fore the	MX lookups may go away in a future release.

       The  mda	 and plugin options interact badly.  In	order to collect error
       status from the MDA, fetchmail has to change its	normal signal handling
       so that dead plugin processes do	not get	reaped until the  end  of  the
       poll cycle.  This can cause resource starvation if too many zombies ac-
       cumulate.   So either do	not deliver to a MDA using plugins or risk be-
       ing overrun by an army of undead.

       The --interface option does not support IPv6 and	it is doubtful	if  it
       ever  will,  since there	is no portable way to query interface IPv6 ad-
       dresses.

       The RFC822 address parser used in multidrop mode	chokes on  some	 @-ad-
       dresses	that are technically legal but bizarre.	 Strange uses of quot-
       ing and embedded	comments are likely to confuse it.

       In a  message  with  multiple  envelope	headers,  only	the  last  one
       processed will be visible to fetchmail.

       Use  of	some  of  these	protocols requires that	the program send unen-
       crypted passwords over the TCP/IP connection to the mail	server.	  This
       creates a risk that name/password pairs might be	snaffled with a	packet
       sniffer	or  more  sophisticated	 monitoring software.  Under Linux and
       FreeBSD,	the --interface	option can be  used  to	 restrict  polling  to
       availability  of	 a  specific interface device with a specific local or
       remote IP address, but snooping is still	possible if  (a)  either  host
       has a network device that can be	opened in promiscuous mode, or (b) the
       intervening network link	can be tapped.	We recommend the use of	ssh(1)
       tunnelling  to  not  only  shroud your passwords	but encrypt the	entire
       conversation.

       Use of the %F or	%T escapes in an mda  option  could  open  a  security
       hole, because they pass text manipulable	by an attacker to a shell com-
       mand.  Potential	shell characters are replaced by '_' before execution.
       The hole	is further reduced by the fact that fetchmail temporarily dis-
       cards  any  set-uid  privileges it may have while running the MDA.  For
       maximum safety, however,	do not use an mda command containing %F	or  %T
       when fetchmail is run from the root account itself.

       Fetchmail's  method  of	sending	bounces	due to errors or spam-blocking
       and spam	bounces	requires that port 25 of localhost  be	available  for
       sending mail via	SMTP.

       If you modify ~/.fetchmailrc while a background instance	is running and
       break  the syntax, the background instance will die silently.  Unfortu-
       nately, it cannot die noisily because we	do not yet know	whether	syslog
       should be enabled.  On some systems, fetchmail  dies  quietly  even  if
       there is	no syntax error; this seems to have something to do with buggy
       terminal	ioctl code in the kernel.

       The  -f	-  option (reading a configuration from	stdin) is incompatible
       with the	plugin option.

       The 'principal' option only handles Kerberos IV,	not V.

       Interactively entered passwords are truncated after 63  characters.  If
       you  really  need to use	a longer password, you will have to use	a con-
       figuration file.

       A backslash as the last character  of  a	 configuration	file  will  be
       flagged as a syntax error rather	than ignored.

       The  BSMTP error	handling is virtually nonexistent and may leave	broken
       messages	behind.

       Send comments, bug reports, gripes, and the like	to the fetchmail-devel
       list <mailto:fetchmail-devel@lists.sourceforge.net>

       An	  fetchmail	    FAQ		(in	    HTML	 form)
       <https://fetchmail.sourceforge.io/fetchmail-FAQ.html>  is  available at
       the fetchmail home page,	it should also accompany your installation.

AUTHOR
       Fetchmail is currently maintained by Matthias Andree and	Rob Funk  with
       major  assistance  from	Sunil Shetye (for code)	and Rob	MacGregor (for
       the mailing lists).

       Most    of     the     code     is     from     Eric	S.     Raymond
       <mailto:esr@snark.thyrsus.com>.	 Too  many  other  people to name here
       have contributed	code and patches.

       This program is descended from and replaces popclient, by  Carl	Harris
       <mailto:ceharris@mal.com>;  the	internals have become quite different,
       but some	of its interface design	is directly traceable to  that	ances-
       tral program.

       This  manual page has been improved by Matthias Andree, R. Hannes Bein-
       ert, and	Hector Garcia.

SEE ALSO
       README,	  README.SSL,	 README.SSL-SERVER,    The    Fetchmail	   FAQ
       <https://www.fetchmail.info/fetchmail-FAQ.html>,	   mutt(1),    elm(1),
       mail(1),	sendmail(8), popd(8), imapd(8),	netrc(5), the  fetchmail  home
       page	  <https://www.fetchmail.info/>,       (alternative	  URI)
       <https://fetchmail.sourceforge.io/>;   the    maildrop	 home	 page.
       <https://www.courier-mta.org/maildrop/>

APPLICABLE STANDARDS
       Note that this list is just a collection	of references and not a	state-
       ment  as	 to  the actual	protocol conformance or	requirements in	fetch-
       mail.

       SMTP/ESMTP:
	    RFC	821, RFC 2821, RFC 1869, RFC 1652, RFC	1870,  RFC  1983,  RFC
	    1985, RFC 2554.

       mail:
	    RFC	822, RFC 2822, RFC 1123, RFC 1892, RFC 1894.

       POP2:
	    RFC	937

       POP3:
	    RFC	 1081,	RFC  1225, RFC 1460, RFC 1725, RFC 1734, RFC 1939, RFC
	    1957, RFC 2195, RFC	2449.

       APOP:
	    RFC	1939.

       RPOP:
	    RFC	1081, RFC 1225.

       IMAP2/IMAP2BIS:
	    RFC	1176, RFC 1732.

       IMAP4/IMAP4rev1:
	    RFC	1730, RFC 1731,	RFC 1732, RFC 2060, RFC	2061,  RFC  2195,  RFC
	    2177, RFC 2683.

       ETRN:
	    RFC	1985.

       ODMR/ATRN:
	    RFC	2645.

       OTP: RFC	1938.

       LMTP:
	    RFC	2033.

       GSSAPI:
	    RFC	 1508,	RFC 1734, Generic Security Service Application Program
	    Interface  (GSSAPI)/Kerberos/Simple	 Authentication	 and  Security
	    Layer		(SASL)		    Service		 Names
	    <https://www.iana.org/assignments/gssapi-service-names/>.

       TLS: RFC	2595.

fetchmail 6.4.38		  2022-10-30			  FETCHMAIL(1)

NAME | SYNOPSIS | DESCRIPTION | SUPPORT, TROUBLESHOOTING | TLS (SSL) QUICKSTART | CONCEPTS | PREFACE ON THIS MANUAL | GENERAL OPERATION | USER AUTHENTICATION AND ENCRYPTION | POP3 VARIANTS | ALTERNATE AUTHENTICATION FORMS/METHODS | DAEMON MODE | ADMINISTRATIVE OPTIONS | RETRIEVAL FAILURE MODES | SPAM FILTERING | SMTP/ESMTP ERROR HANDLING | THE RUN CONTROL FILE | KEYWORD/OPTION SUMMARY | DEBUGGING FETCHMAIL | INTERACTION WITH RFC 822 | CONFIGURATION EXAMPLES | THE USE AND ABUSE OF MULTIDROP MAILBOXES | SOCKS | EXIT CODES | FILES | ENVIRONMENT | SIGNALS | BUGS, LIMITATIONS, AND KNOWN PROBLEMS | AUTHOR | SEE ALSO | APPLICABLE STANDARDS

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