$pattern = '[01]?[0-9]?[0-9]|2[0-4][0-9]|25[0-5]';

/(?:(${pattern})\.){3}($pattern)/;  # "$1.$2.$3.$4" = IP if matched

##</code><code>##

sub get_octets {
    my @octets = split(/\./, shift);
    return unless @octets == 4;

    foreach (@octets) {
        $_ += 0;   # Perhaps unnecessary, but forces the "octet" to be numeric or zero
        return unless $_ >= 0 && $_ <= 255;
    }

    return @octets;
}