my $ip_mask = parse_ip_mask('131.202.1.[3-4]');

foreach (
   'Connection established to 131.202.1.2',
   'Connection established to 131.202.1.3',
   'Connection established to 131.202.1.4',
   'Connection established to 132.202.1.4',
) {
   my ($ip) = /(\d+\.\d+\.\d+\.\d+)/;
   print("Found matching ip $ip.$/") if (ip_check($ip, $ip_mask));
}

__END__
output
======
Found matching ip 131.202.1.3.
Found matching ip 131.202.1.4.