Welcome to the home of Kuls 'DNS Resolving NameServer Checker' script

This page deals with DNS Resolving NameServer Checker written in perl. This simple perl script allows you to check if the Resolving NameServers are actually responding. Useful if your server is using third party NameServers for Resolution - Written because those of us who use(d?) UK2 have extreme issues with repeated lack of availability of the UK2 provided NameServers. This script has been written to be able to be executed in a Linux(/UNIX?) environment, but also works perfectly well under Windows using ActivePerl, and no doubt almost anywhere that perl is installed.

Resolving NameServers are NOT the regular NameServers you enter for each domain's DNS Zone you setup. The Resolver is the software that your server (and PC) will use to lookup anything and everything that is Internet related. For example, if you wish to connect to your server, it is extremely likely that it will be setup to check what your Reverse IP settings are, this requires the Resolver to use a NameServer to supply it with the answer. Even if somebody tries to send you an e-mail to your Server, this requires that their IP is looked up as well, and requires the Resolver. It is absolutely essential that your Resolver's NameServers are all kept working all the time, failure to keep them in tip-top condition will result in Time outs during connection to the server (for everyone, doing anything), which is irritating at best, and will almost certainly loose you visitors / customers.

I wrote this script to allow me to quickly check if my Server's DNS Resolving NameServers were functioning correctly.
This is a PERL script, it is NOT a perl CGI script, it can ONLY be run from a SSH/Telnet Session. It IS possible to convert this to a CGI script and run it from a web site. You can see a CGI version (not publicly available - please don't e-mail me for it either) at http://akakul.co.uk/dns_check_resolver

This perl script needs to be installed via Shell (Telnet/SSH) and can be run from any user. 'root' access is not required.

Source Formats Available: Plain Text (UNIX) | GZ (GZiped Compressed) | ZIP (Windows Format Compressed), Download your chosen Format now

Installing

You can either download your chosen format to the server directly (recommend GZ file), or to your PC and FTP (this is a UNIX file and should be uploaded as BINARY - NOT ASCII) up to a user account.
Then ensure it has 700 (or greater permissions) - 'chmod 700 dns_check_resolver.pl'
  or follow these instructions:

cd some_directory
wget http://akakul.co.uk/code/dns_check_resolver.gz
gunzip dns_check_resolver.gz
chmod 700 dns_check_resolver.pl

Now you can either execute it without any parameters and it will read the contents of '/etc/resolv.conf' if it can be found and use the entries it finds in there ('nameserver nnn.nnn.nnn.nnn'), or you can execute it with a list of IP addresses (IPv4 only) as parameters and the checker will use those as the list of IP addresses to check.

./dns_check_resolver.pl

or enter the IP's to check (replace nnn.nnn.nnn.nnn with an IP)

./dns_check_resolver.pl nnn.nnn.nnn.nnn

References:

• CGI Version: http://akakul.co.uk/dns_check_resolver