Reverse DNS does not match SMTP Banner

Question

It appears that this question, or ones similar, have been asked previously, but I did not find a solution in the responses that were given. 
 
 Here is my scenario... 
 I have a Exchange server behind the UTM that hosts multiple domains (my own personal domains). Recently I have been experiencing more occasions where mail messages sent from my domains are ending up in a users junk/spam folder. Obviously this is undesirable. 
 Tests on MXToolbox return no errors, but there are a few warnings, the one I am most concerned about being "Reverse DNS does not match SMTP Banner" 
 I recently changed ISPs and that meant that my fixed IP changed too. Initially there was a problem with my reverse DNS, but that was resolved. 
 
 On the Exchange server you can configure multiple Send Connectors (one for each domain) and these normally deal with the HELO/EHLO requests. However, these are overridden by the UTM (Email Protection > SMTP > Advanced > Advanced Settings > SMPT Hostname). It would appear that whatever is set there is what is seen for a HELO/EHLO request. I have tried leaving the SMTP Hostname blank, but that is worse. Then the UTM simply reverts to the UTM's hostname. 
 The end result is that the "Received: from" header does not match any of my email domains, which I assume is causing me the issues. 
 
 I believe that technically I could set the SMTP Hostname on the UTM to the MX name of one of my domains and set the MX records of my other domains to match, but that would be quite undesirable. I need the Received header to match the hostname of the email being sent. Receiving mail to multiple domains is not an issue at all. 
 
 So, this is my question... 
 Is there a way I can use the SMTP proxy on the UTM but have my Exchange Send Connectors do the HELO/EHLO response? 
 Or maybe there is another way I can get around this issue of multiple email domains behind the UTM. 
 
 As always, I am open to suggestions. 
 
 UTM v9.502-4 
 Home License

DouglasFoster · Accepted Answer

I run an email environment with multiple domains, and I think your spam problem lies elsewhere. 
 The method for configuring an rdns entry for youself is called SWIP, which I believe stands for Shared Whois for IP. Your ISP helps set it up. 
 You pick one host name and use it for all of the mx records, for the swip record, and for the smtp hostname in EHLO. 
 If you are sending high volume, you may need to register all of the above wifh aol, yahoo, google, etc. Their requirements differ, and some may appear to require one rdns for each domain, but they have been reasonable in my experience. 
 The most important step is to collect examples of blocked mail. The headers usually provide valuable insight. Then check with the admins of those services if you still have unanswered questions. 
 Because so much legitimate email is sent by third parties, I have never seen a spam rule that links the server name to any other message content. 
 You do need to ensure that all of your email is clean. In a multi-client environment, one misbehaving client can blacklist your server, causing problems for all clients.

Ol Deda · Answer

Your IP can have only one PTR record or RDNS name. Has nothing to do with sophos hostname The simple way is to put that hostname in every MX record