use Socket qw/inet_aton inet_ntoa/;

my $base = '1.1.1.1';
my $nbase = unpack 'N',inet_aton($base);

my @quads = map { inet_ntoa(pack('N', $_)) }
            grep { $_ % 256 }
            $nbase .. 2000 + $nbase;

{
    local $, = ' ';
    print @quads, $/;
}