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dhcpagent(1M)		System Administration Commands		 dhcpagent(1M)

       dhcpagent - Dynamic Host	Configuration Protocol (DHCP) client daemon

       dhcpagent [-a] [	-d n] [-f] [-v]

       dhcpagent  implements the client	half of	the Dynamic Host Configuration
       Protocol	(DHCP) for machines running Solaris software.

       The dhcpagent daemon obtains configuration parameters  for  the	client
       (local)	machine's network interfaces from a DHCP server. These parame-
       ters may	include	a lease	on an IP address, which	gives the  client  ma-
       chine  use of the address for the period	of the lease, which may	be in-
       finite. If the client wishes to use the IP address for a	period	longer
       than  the  lease,  it  must negotiate an	extension using	DHCP. For this
       reason, dhcpagent must run as  a	 daemon,  terminating  only  when  the
       client machine powers down.

       The  dhcpagent  daemon  is  controlled through ifconfig(1M) in much the
       same way	that the init(1M) daemon is controlled by telinit(1M).	dhcpa-
       gent may	be invoked as a	user process, albeit one requiring root	privi-
       leges, but this is not necessary, as ifconfig(1M) will start  it	 auto-

       When invoked, dhcpagent enters a	passive	state while it awaits instruc-
       tions fromifconfig(1M). When it receives	a command to configure an  in-
       terface,	 it  starts  DHCP.  Once  DHCP	is  complete, dhcpagent	may be
       queried for the values of the various network parameters. In  addition,
       if  DHCP	was used to obtain a lease on an address for an	interface, the
       interface is configured and brought up. When a lease is obtained, it is
       automatically  renewed  as  necessary.  If the lease cannot be renewed,
       dhcpagent will take the interface down at the end of the	lease. If  the
       configured  interface  is  found	to have	a different IP address,	subnet
       mask or broadcast address from those obtained from DHCP,	the  interface
       is abandoned from DHCP control.

       In  addition to DHCP, dhcpagent also supports BOOTP. See	RFC 951, Boot-
       strap Protocol. Configuration parameters	obtained from a	 BOOTP	server
       are  treated  identically  to those received from a DHCP	server,	except
       that the	IP address received from a BOOTP server	always has an infinite

       DHCP  also acts as a mechanism to configure other information needed by
       the client, for example,	the domain  name  and  addresses  of  routers.
       Aside  from  the	 IP  address,  netmask,	 broadcast address and default
       router, the agent does not directly configure the workstation, but  in-
       stead  acts  as a database which	may be interrogated by other programs,
       and in particular by dhcpinfo(1).

       On clients with a single	 interface,  this  is  quite  straightforward.
       Clients	with  multiple	interfaces  may	present	difficulties, as it is
       possible	that some information arriving	on  different  interfaces  may
       need  to	be merged, or may be inconsistent. Furthermore,	the configura-
       tion of the interfaces is asynchronous, so requests  may	 arrive	 while
       some  or	 all of	the interfaces are still unconfigured. To handle these
       cases, one interface may	be designated as primary, which	makes  it  the
       authoritative  source  for  the	values	of DHCP	parameters in the case
       where no	specific interface is requested. See  dhcpinfo(1)  and	ifcon-
       fig(1M) for details.

       The  dhcpagent  daemon  can  be configured to request a particular host
       name. See the REQUEST_HOSTNAME description in the FILES	section.  When
       first configuring a client to request a host name, you must perform the
       following steps as root to ensure that the full DHCP negotiation	 takes

       # pkill dhcpagent
       # rm /etc/dhcp/interface.dhc
       # reboot

       The dhcpagent daemon writes information and error messages in five cat-

		    Critical messages indicate severe conditions that  prevent
		    proper operation.

		    Error  messages  are  important,  sometimes	 unrecoverable
		    events due to resource  exhaustion	and  other  unexpected
		    failure  of	 system	calls; ignoring	errors may lead	to de-
		    graded functionality.

		    Warnings indicate less severe problems, and	in most	cases,
		    describe  unusual  or  incorrect  datagrams	 received from
		    servers, or	requests for service that cannot be provided.

		    Informational messages provide key pieces  of  information
		    that  can be useful	to debugging a DHCP configuration at a
		    site. Informational	messages are generally	controlled  by
		    the	 -v option. However, certain critical pieces of	infor-
		    mation, such as the	IP address obtained, are  always  pro-

	      debug Debugging  messages, which may be generated	at two differ-
		    ent	levels of verbosity, are chiefly of benefit to persons
		    having access to source code, but may be useful as well in
		    debugging difficult	DHCP configuration problems. Debugging
		    messages are only generated	when using the -d option.

       When  dhcpagent	is run without the -f option, all messages are sent to
       the system logger syslog(3C) at the appropriate matching	 priority  and
       with  a	facility identifier LOG_DAEMON.	When dhcpagent is run with the
       -f option, all messages are directed to standard	error.

       The following options are supported:

	      -a    Adopt a configured interface. This option is for use  with
		    diskless  DHCP clients. In the case	of diskless DHCP, DHCP
		    has	already	been performed on the network  interface  pro-
		    viding  the	operating system image prior to	running	dhcpa-
		    gent. This option instructs	the agent to take over control
		    of the interface. It is intended primarily for use in boot

	      -d n  Set	debug level to n. Two levels  of  debugging  are  cur-
		    rently available, 1	and 2; the latter is more verbose.

	      -f    Run	in the foreground instead of as	a daemon process. When
		    this option	is used, messages are sent to  standard	 error
		    instead of to syslog(3C).

	      -v    Provide  verbose output useful for debugging site configu-
		    ration problems.

	     Contains the configuration	for interface. The mere	 existence  of
	     this file does not	imply that the configuration is	correct, since
	     the lease may have	expired.

	     Contains default values for tunable parameters. All values	may be
	     qualified	with the interface they	apply to by prepending the in-
	     terface name and a	period (".") to	the interface parameter	 name.
	     The parameters include:

		   Indicates  that a RELEASE rather than a DROP	should be per-
		   formed on managed interfaces	when the agent terminates.

		   Indicates how long to wait between checking for  valid  OF-
		   FERs	after sending a	DISCOVER.

		   Indicates how long to wait for clients to respond to	an ARP
		   request before concluding the address in the	ARP request is

		   Specifies whether or	not the	agent should assume an address
		   is available, in the	unlikely event that ARP	cannot be per-
		   formed on that address.

		   Indicates  the  value that should be	used to	uniquely iden-
		   tify	the client to the server.

		   Specifies a list of comma-separated integer values  of  op-
		   tions for which the client would like values.

		   Indicates  the  client  requests the	DHCP server to map the
		   client's leased IP address to the host name associated with
		   the network interface that performs DHCP on the client. The
		   host	name must be specified in the  /etc/hostname.interface
		   file	for the	relevant interface on a	line of	the form

		   inet	hostname

		    where hostname is the host name requested.

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE	TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWcsr			   |
       |Interface Stability	     |Evolving			   |

       dhcpinfo(1), ifconfig(1M), init(1M), syslog(3C),	attributes(5), dhcp(5)

       System Administration Guide: IP Services

       Croft,  B.  and	Gilmore, J.,Bootstrap Protocol (BOOTP)RFC 951, Network
       Working Group, September	1985.

       Droms, R., Dynamic Host Configuration Protocol, RFC 2131, Network Work-
       ing Group, March	1997.

       Currently,  configurations where	more than one interface	is attached to
       the same	physical network are unsupported. This precludes use  of  vir-
       tual interfaces.

SunOS 5.9			  13 Mar 2001			 dhcpagent(1M)


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