123.123.123.123 124.124.124.124 Canada BC
111.111.111.111 112.112.112.112 Canada AB
11.11.11.11 12.12.12.12 USA WA
22.22.22.22 23.23.23.23 USA OR
33.33.33.33 34.34.34.34 USA CA

##</code><code>##

10.10.10.10
11.11.12.12
123.123.122.122
123.123.124.125

##</code><code>##

#!perl
#

use strict ;
use warnings ;
	                 
open INFO, 'IPs.txt' or die $! ;
chomp( my @IPs = <INFO> ) ;
close INFO ;

my @rows = () ;
open IN, ' source.txt' or die $! ;
while (<IN>)
{
    next if /^$/ ;
    my %table = () ;
    @table{ 'ip', 'ip2', 'country', 'region' } = split ;
    $table{ 'num_ip' }  = sprintf '%03d' x 4, split /\./, $table{ 'ip' } ;
    $table{ 'num_ip2' } = sprintf '%03d' x 4, split /\./, $table{ 'ip2' } ;
    push @rows, \%table ;
}
close IN;

open OUT, '>>conversion.txt' or die $! ;
foreach my $ip ( @IPs )
{                                       
    my $match = 0 ;
    my $num_ip = sprintf '%03d' x 4, split /\./, $ip ;
    foreach my $row ( @rows )
    {
        if ( $num_ip >= $row->{'num_ip'} && $num_ip <= $row->{'num_ip2'} )
        {
            printf OUT "%-16s %s\n", $ip, $row->{'region'} ;
            $match++ ;
        }
    }
    printf OUT "%-16s\n", $ip if !$match ;
}
close OUT;

##</code><code>##

10.10.10.10     
11.11.12.12      WA
123.123.122.122 
123.123.124.125  BC