Hi all - I need some help -arrrggggggggghhhhhI changed our modem at work on Friday afternoon - set it all up, have managed to get all the networks & internet going, but now for some reason we cannot send or receive any emails through Exchange 2003. Our service provider tells me that the modem is not configured properly....Any help appreciated

What is the modem, and who is the ISP? I am guessing you have a full business account with your ISP, and as such, no ports are being blocked on their end. Is it possible to bridge or make the modem a full passthrough to a firewall or some other device behind it, this way you have fuller control over what is allowed into the network? I know this does not help much, but does give some things to think about and with the modem specs, possibly someone here will be able to give a fuller answer.