Find out DNS Server Version With DNS Server Fingeprinting tool

Posted on in Categories Debian Linux, FreeBSD, Howto, Linux, Networking, Security, Sys admin, Tip of the day, UNIX last updated September 27, 2007

By hiding out DNS server version number you can improve server security. fpdns is a program that remotely determines DNS server versions. It does this by sending a series of borderline DNS queries which are compared against a table of responses and server versions. (just like nmap command’s remote OS detection facility).

A nameserver basically responds to a query. Interoperability is an obvious requirement here. The standard protocol behavior of different DNS implementations is expected to be the same.

Install fpdns

Debian / Ubuntu user, enter the following command:
$ sudo apt-get install fpdns
FreeBSD user, either use ports or binary package:
$ pkg_add -v -r fpdns
Alternatively grab source code from official web site.

Howto remotely determine DNS server version

To determine DNS server version for domain nixcraft.com, enter:
$ fpdns -D nixcraft.com
Output:

fingerprint (nixcraft.com, 64.202.165.116): bboy MyDNS
fingerprint (nixcraft.com, 208.109.80.52): bboy MyDNS 

You can easily find out if recursion enabled or not:
$ fpdns ns1.vnsl.com.
Output:

fingerprint (ns1.vnsl.com., 69.60.111.228): ISC BIND 9.2.3rc1 -- 9.4.0a0 [recursion enabled]  

To read list of servers from key board, enter:
$ fpdns -
Output:

ns2.vnsl.com
fingerprint (ns2.vnsl.com, 64.85.160.11): ISC BIND 9.2.3rc1 -- 9.4.0a0 [recursion enabled]
ns1.softlayer.com
fingerprint (ns1.softlayer.com, 66.228.118.8): ISC BIND 9.2.3rc1 -- 9.4.0a0
ns.yahoo.com
fingerprint (ns.yahoo.com, 66.218.71.63): ISC BIND 8.3.0-RC1 -- 8.4.4
ns1.google.com
fingerprint (ns1.google.com, 216.239.32.10): ISC BIND 8.3.0-RC1 -- 8.4.4 

Further readings

=> Read fpdns man page.

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

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