I have an Exchange 5.5 server on W2K machine that works perfectly. I want to install a relay server in front of this machine for antivirus protection. I configured another W2K server with Virtual SMTP server forwarding all mail to existing Exchange 5.5 machine - worked well. Once I tell the Exchange 5.5 machine to forward all mail to the relay server, the mail gets there and then backs up in the Inetpub\mailroot\queue folder and does not get delivered. Starting/stopping the service has no effect. The only thing that does have an effect is rebooting the machine - then SOME of the messages get forwarded as expected - then the flow stops again. I had to reboot about 5 times to get about 60 messages to get delivered. Microsoft has a couple articles indicating that installing the latest service pack shoudl correct this problem, but I installed them all before this whole project. Any help would be GREATLY appreciated.