I have a network running Exchange 2007 with an Edge server in the DMZ and the Hub server on the Lan. I have set up 2 Untangle servers that sit between the firewall and those servers as shwon in the attached diagram...
When the Spam Blocker Lite and/or Web Filter Lite are on, outgoing emails don't leave the Hub server, even with the option "Scan outbound (WAN) SMTP" being unchecked. So I set up the following bypass rules on both UT servers:
- Destination Address 10.165.10.6
- Destination port 25
- Protocol TCP
Email is now being delivered to the outside world but it doean't look like the Spam Filter is catching any incoming spam since the "Messages dropped" and "Messages quarantined" numbers don't change. While the numbers in "Messages passed" increase slowly, there are 3 times more than what's reported that get to the Edge server. And since Exchange on the Edge server also has an integrated spam filter, there are over 2,400 spam emails in the last 24 hours that it caught, mostly via the Block List Provider lists.
My question is, since email traffic transits through the UT server before it gets to the Edge server, why isn't Spam Blocker catching it?