use warnings;
use strict;
use Data::Validate::IP qw(is_ipv4);

while (my $line = <DATA>) {
    chomp $line;
    my($key, $parameter_value) = split("=", $line);
    if (is_ipv4($parameter_value))
    {
      print $parameter_value;
    }
    else {
      print "Fail"
    }
}
print "\n";

__DATA__
abc=1.2.3.4

##</code><code>##

    my($key, $parameter_value) = split("=", $line);
    print ">>>$parameter_value<<<\n";