We are currently deploying a new network. There are two domain controllers (Win 2003 Standard) and an ISA server (2004). The 2nd domain controller is the Exchange Server running Exchange 2003 Standard. The ISA server is connected to a cable modem with a static IP address There is Internet connectivity to each of the servers. We have inbound email but cannot send any outboud. When I try and run a SMTP test utility, I get an "unable to relay to sender" message.