Email Protection - SMTP Log without entries when transparent mode disabled

Hoi Kere and welcome to the UTM Community!

Basic Exchange setup with SMTP Proxy might be helpful, too.

Cheers - Bob
PS The reason you don't want to use Transparent except for debugging purposes is that any infected device could relay off the UTM and get your IP onto all of the blacklists - not fun!

Hi Bob,

I did follow the recommendations but had issues with the mails not being visible in the Mail Manager afterwards.

Adding the smarthost entry on the Exchange server did help to some extend - emails are being received correctly and are visible within the Mail Manager, sending emails isn't working, though.

The outgoing emails only showed up in the log after I reverted back to the old settings.

Any idea what I may have missed?

Kind regards

Kere

"The smart host setting in the SMTP Connector in Exchange Manager must point to the "Internal (Address)" of the Astaro. If you already had a different setting in Exchange, pointing at an external smart host that you must use, you must transfer that to the Astaro's 'Smarthost settings' at the bottom of the 'Advanced' tab."

You should not use Transparent SMTP Proxy except to debug.  You've now proven that Exchange was sending emails directly out instead of using the SMTP Proxy as a smart host.  I'll guess that the smart host setting that Exchange is using is still your old smart host or, if you didn't have a smart host setting before, that your smart host setting in Exchange isn't done correctly.  That setting should have nothing to do with whether Exchange can receive emails - I bet you're now seeing inbound emails in the SMTP log because you disabled the old DNAT that you had that forwarded emails directly to your server.

Cheers - Bob

Hi Bob,

I used the following settings on the UTM and Exchange Server:

UTM

Network Protection > NAT - Exchange DNAT rule disabled

SMTP > Global - Simple Mode

SMTP > Routing - Domain: my Domain, host list: my Exchange Server, verify recipients: with callout

SMTP > Malware - Standard Settings, dual scan

SMTP > AntiSpam - Standard Settings

SMTP > Data Protection - Standard Settings

SMTP > Exceptions - communication to VOIP server

SMTP > Relaying - allowed Hosts/Networks: my Exchange Server, scan relayed (outgoing) Messages: ticked

SMTP > Advanced - transparent mode: ticked, SMTP hostname: mail.mydomain; use smarthost: not ticked

Exchange Server

mail flow > send connectors > active connector > delivery > smarthost: internal IP of firewall

Prior to the change, the send connector was using the associated MX entry to send the emails.

Previously a different connector was used which had a smarthost defined.

It shouldn't have an impact as it's set to inactive and the parameters aren't longer valid either.

Am I missing another Setting with the Exchange configuration?

Kind regards

Kere

That all seems right, Kere.

Is the Host object for the Exchange server the same one on both the 'Routing' and 'Relaying' tabs?

The only other thing I can think of is a packet capture that sees what destination IP Exchange is sending to.  That should give a hint as to what the problem is.

Cheers - Bob

That all seems right, Kere.

Is the Host object for the Exchange server the same one on both the 'Routing' and 'Relaying' tabs?

The only other thing I can think of is a packet capture that sees what destination IP Exchange is sending to.  That should give a hint as to what the problem is.

Cheers - Bob