dnstop is a tool for monitoring DNS network traffic. Download it at:

http://pkgs.repoforge.org/dnstop/

After installation, run:

dnstop {interface-name}

to monitor DNS traffic. For example, to monitor eth0:

dnstop eth0

Example command output

Queries: 55 new, 1224 total  Thu Jul 12 21:36:20 2012

Sources             Count      %
--------------- --------- ------
216.179.252.71       1217   99.4
110.164.252.214         2    0.2
203.113.5.243           1    0.1
203.113.7.245           1    0.1
67.215.80.19            1    0.1
203.158.4.45            1    0.1
202.80.233.23           1    0.1

Option help

s - Sources list d - Destinations list t - Query types o - Opcodes r - Rcodes 1 - 1st level Query Names ! - with Sources 2 - 2nd level Query Names @ - with Sources 3 - 3rd level Query Names # - with Sources 4 - 4th level Query Names $ - with Sources 5 - 5th level Query Names % - with Sources 6 - 6th level Query Names ^ - with Sources 7 - 7th level Query Names & - with Sources 8 - 8th level Query Names * - with Sources 9 - 9th level Query Names ( - with Sources ^R - Reset counters ^X - Exit ? - this