I have recently implemented a FE/BE configuration for security reasons. OWA
works perfectly when connecting to the front end. But, if someone using
IMAP or POP when attaching to the FE, the Client (we are using Outlook
express) gives an error like the following:
The message could not be sent because one of the recipients was rejected by
Subject '', Account: 'IMAP Mail', Server: '192.168.1.92', Protocol: SMTP,
Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79
Now, the BE server has been configured for SMTP relay for a while, and IMAP
and POP3 works fine if you connect to it. But the FE is the problem. I
read some posts about setting up a Smart Host in SMTP, but I didn't know
exactly what they meant and I tried it and it didn't work on the FE and BE.
I also configured the FE SMTP relay exactly the same as the BE relay.
Any suggestions on how to set this up? Or where I went wrong?