I have exchange 5.5, sp4 running on win2k server. We have several unix, sun servers that eventually need to send email for backups and schedule jobs to internal users. And they leave the unix servers but never make it to the receipient. My querstion is, Is there a routing or relaying issue that my exchage server doesn't have enable or do you think is at the unix side level? Have any of you had any issues like this? thanks