Hi Alex,
SWEP is Symantec Web Email Protection or Web Messenger (Symantec Change the names and cause confusion, becomes a puzzle)
The fact is that the client wants all messages (encrypted or unencrypted) are sent only by the "message filter" server. He does not want to enable more traffic SMTP in the firewall's perimeter.
The flow would be:
Message not encrypted:
Mail Server -> Message Filter Server -> Perimeter Firewall -> Internet.
Message encrypted with Web Messenger
Mail Server -> Message Filter Server -> Universal Servver -> Message Filer Server (again) -> Perimeter Firewall -> Internet.
In a test environment, I tried to configure the Universal Server in Mail -> Proxies -> SMTP with:
SMTP Proxy: Otbound
and select Proxy mail to SMTP server:
In Host I type the IP of the Symantec Messaging Gateway's port (to emulate the environment).
While reviewing the message tracking in SMG do not see that pass messages Web Messenger, However, the mail arrives encryption. I checked the headers and noticed that the Universal Server remains who sent it.
For testing I have enabled SMTP traffic for Universal server in the firewall.
Any idea, thank you.