Here is our configuration; We accept all inbound messages to our gateway servers. Our imail server is not listed in the MX records for the domain and we do not want messages to get to our imail server without first touching a gateway server unless the user has authenticated. I'm not having any luck figuring out how to accomplish this. I am getting unwanted SPAM that makes it through the iMail spam checks that would normally be caught by our gateway servers.
I cannot limit access to tcp port 25 on the firewall without effecting the authenticated user.
Am I missing something here? Is there a setting or settings that can help me accomplish this?
Any help is greatly appreciated
1) Have all of your users configure their email program to send outgoing email to port 587, not the default port 25. This port is specified as the SMTP Auth port and Imail and other email servers can be configured to accept outgoing email through this port ONLY if the user has authenticated.
2) On your firewall, redirect incomfing port 25 traffic to port 587.
"Life is a succession of lessons which must be lived to be understood." Ralph Waldo Emerson (1802-1882)