---If I understand SMTP gateway or some call it SMTP relay, is where the anti virus and anti spam software is installed on the same box as exchange2003 (without mailboxes), so that emails coming in from internet are scanned before they are forwarded to the Front end server.
correct me if I am wrong
--emails going from inside to internet should not go through this SMTP gateway/relay, but have seen some configuration that make it go through it. what 's the reason ?
---if possible, can someone tell me how Exchange Front end is able to determine such email has its user mailbox in Exchange server 1 and such email has its user mailbox in exchange server 2 ???