Build?

Good point. Running 8874 (Apr 18, 2024). Will upgrade to 8888 (May 2, 2024), but don't see any changes to Reverse DNS in release notes.

Are you caching the DNS replies?

Not sure. Where is the setting for DNS caching?

It's only with certain messages, so don't think it's related to caching. A message is received via SMTP and Reverse DNS passes, then less than 1 second later Reverse DNS fails during delivery.

Kevin,

In Settings > Protocols, you should see the SMTP Out card: The first toggle at the bottom of the card will enable DNS caching. Let me know if this helps! 

Hi Joel, thanks for the help finding DNS Caching.  I'm not really having an issue with the speed of message delivery, so not sure this applies. Should it be enabled or disabled?

Plus, this is for SMTP Out and I'm not having an issue with messages going out. The problem message is one being delivered to user mailboxes.

On a totally separate note, your SMTP Out online help has this bullet:

But just FYI, that toggle is not in the current version of SmarterMail. Maybe tell the person who maintains your online help.

Kevin

Analyze the configuration of Spool Filtering and see if you can adjust it to rely less on RDNS and focus more on other spam indicators like sender reputation or content analysis

From my understanding older builds had some DNS issues because of .net framework, and moving to the .net core builds resolves some of this. We had the September 2023 release and had a lot of the same issues where incoming mail would fail reverse DNS lookups for the remote server, even though they definitely existed. Some days were horrible. Most of this seems to be better in recent builds.

OK, we're on build 8888 and still seeing this problem. Now occurring with eBay messages.

Reverse DNS passes during SMTP, but fails during Spool so the message goes to Spam folder. Turning off Spool Filtering fixes it, but then we lose the Forward Confirm Fail+Mismatch scores.

File a ticket for SM :)

Good call. I was hoping they would respond here...