We have a 3com NBX phone system on the same network as a SBS 2003 (fully patched) server. The off-site notification for our company e-mail will not work with Exchange because it uses the Public IP address for the URL (ex., mail.mycompany.com) of our company when trying to send the off-site notifications. We have watched the traffic and we see the public IP no matter what we set the NBX SMTP information too. We have talked with 3com but they do not understand how Exchange and Public verses Priviate IP's are handled on a network. We have IIS web servers that can send local e-mail, all-in-one copiers, etc. and all work fine with the SMTP.