Basically I’m trying to block access to login to certain mail boxes (managed by exim) from some countries. Routine is in Perl, so I can easily find IP address of a host using DNS lookup. All I needed was a service to give the location based on incoming IP address. I used rbldnsd and modified it to accept MaxMind country database and wola, it works as expected.

To use, first reverse the IP, just like what you do with RBL based spam lists. For instance 204.50.14.1 will be 1.14.50.204, then combine it with .rbloc.dayanadns.com and make a DNS query to find IP address, for example:

$host 1.14.50.204.rbloc.dayanadns.com

That will give you two records, an A record and a TXT record.

‘A’ record will be in form of 127.0.X.Y wherre X is the ASCII code of the first letter of country code and Y is the second letter. For our example returned IP is 127.0.67.65 which means ‘CA’ (C=> 67, A=>65).

TXT record is the complete country name, i.e. ‘Canada’.

Here is a sample perl script to get the country code:

#!/usr/bin/perl

use Socket;

$packed_ip = gethostbyname('1.14.50.204.rbloc.dayanadns.com');
if (defined $packed_ip)
{
    $ip_address = inet_ntoa($packed_ip);
    my(undef, undef, $d1, $d2) = split(/\./, $ip_address);
    $country_code = chr($d1).chr($d2);
}
print "Result address: ".$ip_address."\n";
print "Country code: ".$country_code."\n";

and this one is in PHP:

<?php

$ip_address = gethostbyname('1.14.50.204.rbloc.dayanadns.com');
list($d1,$d2,$d3,$d4) = explode('.',$ip_address);
$country_code = chr($d3).chr($d4);

print "Result address: ".$ip_address."\n";
print "Country code: ".$country_code."\n";

?>

Code written in Perl and can be executed at a root access shell with a command like this:

perl dysqlcheck.pl

No installation will be needed Just download to a folder and execute. You might need to change some configuration parameters at the beginning of the script itself.

Download Dayana MySQL Database Check v1.0
Current version: 1.0

If you wish to do that on a linux shell do:

cd
wget http://farhad.ca/file/dysqlcheck.pl_
mv -f dysqlcheck.pl_ dysqlcheck.pl
perl dysqlcheck.pl

F.Malekpour