Basic 'net send' probably doesn't work because a lot of ISP's now block ports 135, 137-139, and occasionally 445. There is however another way around. For Windows 2000 and later, net send attempts to make it's connection on port 135 by default. If however, the ISP is blocking that port, there is another way. The messenger also listens on an ephemeral port (1024 or higher). Why Microsoft chose to do it that way, I'll never know. But if you can figure which port messenger is listening on (usually 1024-1028 or in that general area) and send the message to that port, it gets through just fine and messenger pops up just as if port 135 were wide open. The scum who use messenger to send spam started figuring this out, as I occasioanlly see messenger traffic to these ports on my cable modem connection. So the answer is, yes, it can be done, but since I'm not a big fan of the service, I'll leave it to you to figure out how.