I am using GFI MailEssentials v12 on an Exchange 2003 front end server. I have all the filters set to move the SPAM to the Junk Mail folder and it's working great. I also support two other organizations that have their own Exchange 2003 server (as part of SBS). I cannot join these other servers into my domain but I am wondering if it is possible to use GFI to act as the SPAM Filter for the other domains.
My theory is to set the other org's primary MX records to my front-end server then setup an SMTP connector which relays those particular domain names to their appropriate mail servers. I have set this up as a test and it works great, except for the SPAM filtering. SPAM is appropriately sent to my Junk Mail folder on the 'main' server, but they go right into the inbox on the other two servers.
I would like to avoid using the other options like adding SPAM to the subject or header info, as that requires some rules to be setup on the user's end for automatic filtering.
Any ideas are appreciated!