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DNSTOP(8)		    System Manager's Manual		     DNSTOP(8)

NAME
       dnstop -- displays various tables of DNS	traffic	on your	network

SYNOPSIS
       dnstop	[-46apsQR]   [-b   expression]	 [-i   address]	  [-f  filter]
	      [-r interval] [device] [savefile]

DESCRIPTION
       dnstop is a small tool to  listen  on  device  or  to  parse  the  file
       savefile	 and  collect  and print statistics on the local network's DNS
       traffic.	You must have read access to /dev/bpf*.

COMMAND	LINE OPTIONS
       The options are as follows:

       -4      count only messages with	IPv4 addresses

       -6      count only messages with	IPv6 addresses

       -Q      count only DNS query messages

       -R      count only DNS reply messages

       -a      anonymize addresses

       -b expression
	       BPF filter expression
	       (default: udp port 53)

       -i address
	       ignore select addresses

       -p      Do not put the interface	into promiscuous mode.

       -r      Redraw interval (seconds).

       -l level
	       keep counts on names up to level	domain name levels.

	       For example, with -l 2 (the default), dnstop will keep two  ta-
	       bles: one with top-level	domain names, and another with second-
	       level  domain  names.   Increasing  the level provides more de-
	       tails, but also requires	more memory and	CPU.

       -f      input filter name

	       The "unknown-tlds" filter includes only queries for  TLDs  that
	       are  bogus.   Useful  for  identifying  hosts/servers that leak
	       queries for things like "localhost" or "workgroup."

	       The "A-for-A" filter includes only A queries for	names that are
	       already IP addresses.  Certain Microsoft	 Windows  DNS  servers
	       have a known bug	that forward these queries.

	       The  "rfc1918-ptr"  filter  includes  only  PTR queries for ad-
	       dresses in RFC1918 space.  These	should never leak from	inside
	       an organization.

	       The  "refused"  filter,	when  used  with  the -R option, tells
	       dnstop to count only replies with rcode REFUSED.

       -n name
	       Only count messages within the domain name

       -P      Print "progress"	messages on  stderr  when  in  non-interactive
	       mode.

       -B buckets
	       Use buckets hash	table buckets.

       -X      Do  not	tabulate  the sources +	query name counters.  This can
	       significantly reduce memory usage on  busy  servers  and	 large
	       savefiles.

       savefile
	       a captured network trace	in pcap	format

       device  ethernet	device (ie fxp0)

RUN TIME OPTIONS
       While  running,	the  following options are available to	alter the dis-
       play:

       s       display the source address table

       d       display the destination address table

       t       display the breakdown of	query types seen

       r       display the breakdown of	response codes seen

       o       display the breakdown of	opcodes	seen

       1       show 1st	level query names

       2       show 2nd	level query names

       3       show 3rd	level query names

       4       show 4th	level query names

       5       show 5th	level query names

       6       show 6th	level query names

       7       show 7th	level query names

       8       show 8th	level query names

       9       show 9th	level query names

       !       show sources + 1st level	query names

       @       show sources + 2nd level	query names

       #       show sources + 3rd level	query names

       $       show sources + 4th level	query names

       %       show sources + 5th level	query names

       ^       show sources + 6th level	query names

       &       show sources + 7th level	query names

       *       show sources + 8th level	query names

       (       show sources + 9th level	query names

       ^R      reset the counters

       ^X      exit the	program

       space   redraw

       ?       help

NON-INTERACTIVE	MODE
       If stdout is not	a tty, dnstop runs in non-interactive mode.   In  this
       case, you must supply a savefile	for reading, instead of	capturing live
       packets.	  After	 reading the entire savefile, dnstop prints the	top 50
       entries for each	table.

HOW MESSAGES ARE COUNTED
       By default dnstop examines only query messages and ignores replies.  In
       this case the response code table is meaningless	and will  likely  show
       100% "Noerror."

       If  you	supply	(only)	the  -R	 command  line option, dnstop examines
       replies and ignores queries.  This allows you  to  see  meaningful  re-
       sponse  code values, as well as all the other tables.  In this case all
       the query attributes (such as type and name) are	taken from  the	 Ques-
       tion section of the reply.

       Note,  however,	that it	is common for a	stream of DNS messages to con-
       tain more queries than replies.	This could happen, for example,	if the
       server is too busy to respond to	every single query, or if  the	server
       is  designed  to	ignore malformed query messages.  Therefore, you might
       want to examine both queries and	replies	by giving both -R and -Q  com-
       mand  line  options.   In  this case, only the response code counts are
       taken from the replies and all other  attributes	 are  taken  from  the
       queries.

AUTHORS
       Duane Wessels (wessels@measurement-factory.com)
       Mark Foster (mark@foster.cc)
       Jose Nazario (jose@monkey.org)
       Sam Norris <@ChangeIP.com>
       Max Horn	<@quendi.de>
       John Morrissey <jwm@horde.net>
       Florian Forster <octo@verplant.org>
       Dave Plonka <plonka@cs.wisc.edu>
       http://dnstop.measurement-factory.com/

BUGS
       Does not	support	TCP at this time.

FreeBSD	9.0			21 March, 2008			     DNSTOP(8)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=dnstop&manpath=FreeBSD+9.0-RELEASE+and+Ports>

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