DNSTOP

Section: Maintenance Commands (8) Local index Up

BSD mandoc

NAME

dnstop - displays various tables of DNS traffic on your network

SYNOPSIS

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

DESCRIPTION

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

-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), will keep two tables: one with top-level domain names, and another with second-level domain names. Increasing the level provides more details, 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 addresses in RFC1918 space. These should never leak from inside an organization.

-Q

count only DNS query messages

-R

count only DNS reply messages

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 display:

s: display the source address table
d: display the destination address table
t: display the breakdown of query types 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, 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, prints the top 50 entries for each table.

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

Unless compiled with -DUSE_PPP the program will not correctly decode PPP frames.

This document was created by man2html, using the manual pages.
Time: 22:01:32 GMT, April 16, 2011