bartrad: You are well advised to use Regexp::Common::net for IP matching, but be aware that by design, these regexes are not "bounded" or "delimited"; used as-is, they may match things you don't consider a proper IP and you may need to define your own regex. In the case of the  $RE{net}{IPv4} dotted-decimal IP matcher, consider:

c:\@Work\Perl\monks>perl -wMstrict -le
"use Regexp::Common qw(net);
 ;;
 my $s = '123456.4.32.123456';
 ;;
 print qq{A: match, captured '$1'} if $s =~ m{ ($RE{net}{IPv4}) }xms;
 ;;
 my $my_ip = qr{ \b $RE{net}{IPv4} \b }xms;
 print qq{B: match, captured '$1'} if $s =~ m{ ($my_ip) }xms;
"
A: match, captured '56.4.32.123'
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