I suggested as much in the CB but the OP persisted in wanting nested loops (hence the fish). Skipping network and/or broadcast addresses is a little trickier when you do it that way, though. Of course the simplest thing is to just install something like Net::Netmask and be done with it (or to just copy the guts into your source if you have to be moduleinstallaphobic for whatever reason; that also was suggested in the CB).