Dnswalk is a DNS debugger. It performs zone transfers of specified
domains, and checks the database in numerous ways for internal
consistency, as well as accuracy.

dnswalk is not for the faint of heart. It should NOT be
used without a firm knowledge of the DNS RFC’s. If you use this
tool for cracking or otherwise evil purposes, the author hereby
considers you a slime-ball. See the end of this README file for
a list of good reading material.

dnswalk [-fradm] domain [> logfile]

dnswalk tends to produce lots of output, so I’d suggest
redirecting this into a file of your choice. I debated using doc’s
strategy of automatically putting it in a logfile, but decided not
to. (The author reserves the right to change his mind) For small,
mostly-correct domains it is pretty manageable, however. For larger
domains, use the included ‘do-dnswalk’ script as a guide.

Options:
-f Force a zone transfer from an authoritative nameserver.
dnswalk normally will look in its saved ‘axfr’ file
for each domain and use that. (if it exists)
-r Recursively descend sub-domains of the specified
domain. Use with caution and care.
-a Turn on warning of duplicate A records. (see below)
-d Some debugging. (Use only if redirecting stdout)
-m Perform checks only if the zone has been modified since
the previous run.
-F perform “fascist” checking. When checking an A record,
compare the PTR name for each IP address with the forward
name and report mismatches. (see below) I recommend
you try this option at least once to see what sorts of
errors pop up - you might be surprised!.
-l Perform “lame delegation” checking. For every NS record,
check to see that the listed host is indeed returning
authoritative answers for this domain. Inspiration for
this comes from the great guys at U-M.

The domain name specified on the command line MUST end with a ‘.’.
You can specify a forward domain, such as “dnswalk pop.psu.edu.”
or a reverse domain, such as “dnswalk 155.118.128.in-addr.arpa.”

(Source: http://www.cpan.org/scripts/netstuff/dnswalk)

Thats all!!

pavs