BTW, in doubt and if you don't believe it you may write a test:

#!/usr/bin/env perl

use strict;
use warnings;
use Data::Validate::IP qw(is_ipv4);
use Test::More tests => 2;

my $perlmonks = q(209.197.123.153);
my $nowhere   = q(192.168.10.991);

ok( defined( is_ipv4($perlmonks) ), qq(ipv4 $perlmonks) );
ok( defined( is_ipv4($nowhere) ),   qq(ipv4 $nowhere) ); 

__END__

karls-mac-mini:playground karl$ ./ip.pl
1..2
ok 1 - ipv4 209.197.123.153
not ok 2 - ipv4 192.168.10.991
#   Failed test 'ipv4 192.168.10.991'
#   at ./ip.pl line 12.
# Looks like you failed 1 test of 2.
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Best regards, Karl