That's interesting. I couldn't get it to work at all at the lower size. Sorry, more specifically: I get "Unknown error at pingsniff.pl at line 132" (the recv call, for each call). When I upped the SIZE it started working. (didn't capitalize for emphasis, the constant is caps.) Hmm. Some kind of problem where the incoming packet is bigger than the maximum size anticipated. "Unknown error" is frustrating; doesn't tell enough about what happened. Well, thanks yet again for your help.