$ perl -le'
use Socket;

sub IP_iter {
    my ( $start, $end ) = map unpack( "N", inet_aton $_ ), @_;
    my $count;
    sub {
        $count = shift;
        $count = $count > $end - $start ? $end - $start + 1 : $count;
        return map inet_ntoa( inet_aton $start++ ), 1 .. $count;
        }
    }

my $ip = IP_iter "1.1.1.1", "1.1.1.12";

print for $ip->( 5 );
print "";
print for $ip->( 5 );
'
1.1.1.1
1.1.1.2
1.1.1.3
1.1.1.4
1.1.1.5

1.1.1.6
1.1.1.7
1.1.1.8
1.1.1.9
1.1.1.10