I need to get an Exchange 5.5 server talking with a smart relay system. Is it correct to set this up via the connection/Address Space/ Routing Address? Setting this to the address of the relay system? when I telnet into port 25 of this system I see the following. ESMTP Sendmail Switch-3.2.2/Switch-3.2.2; Sun, When use this setup, the mail messages are returned with illegal addresses, Like the following. The original message was received at Fri, 20 Apr 2007 10:25:49 -0400 (EDT) from nospam.mail.edu [xxx.xxx.xxx.xx] ----- The following addresses had permanent fatal errors ----- <IMCEASMTP-user+40comcast+2Enet@campus.mail.edu> (reason: 501 Bad address syntax) Any help would be greatly appreciated. Marc

If a 5.5 mailbox without an SMTP address, (e.g. just with a ccMail or X.400 address) sends to an Internet recipient the IMC encapsulates the foreign address into a valid SMTP address. It looks ugly, but it is a valid SMTP address. However, some receiving SMTP hosts don't like the format and consider it illegal. The simplest resolution is to identify the sender and assign an SMTP address. Tony www.activedir.org