Can't get Forwarding Hosts to work in latest version

robetus

Using:
2023-03
Ubuntu 22.04
Sender-dependent transports: Amazon SES SMTP and None/inherit tried.

Seems like it was easy to get Forwarding Hosts working on previous versions but with this one I can’t get it to work. I always get the “loops back to myself” email. I did a lot of research and all of it seems a bit outdated. It’s possible that there is a new configuration I’m not seeing.

I’ve installed the forwarding host I’ve added the forwarding host in my main mailcow server, it adds normally and when I tick Relay this domain or Relay all recipients or both it cannot receive email. Both unchecked works normally. I’ve also whitelisted all the IPs on both severs, there are no IPs being blocked. I have turned off the firewall on both servers to test it.

I’ve add the proper MX records for both the forward host server and the main server to my domain and the MX records have propagated.

I add the forward host server to the main server correct? Not the other way around or do I add both servers to the main and forward host server?

Is there a log file I can look at for specific failure information to troubleshoot this?

I’m stumped, I’ve got this to work before on earlier versions of mailcow easily but now I can’t get it work no matter what I do. Any feedback on what I’m missing would be appreciated.

esackbauer

With “forwarding host” you mean smarthost at Amazon SES?
Use a sender-dependent transport to point to your Amazon SES smarthost(s)
Then you must configure this transport in all domains you want to use that smarthost.
Nothing more is needed.

robetus

I know it’s fairly confusing with all the relay, foward hosts, sender transports but I’m using the names I get from the configuration page inside mailcow which in the case shows “Forwarding Hosts”.

And now that I know how Forwarding Hosts work I will tell everyone here that’s struggling.

You need two mailcow installs, main and alt. You add the same exact domain to both of the installs, in the main install you DO NOT tick Relay domain and Relay all recipients for the domain, you only tick these options in the alt install. Once you have everything installed and ticked you can test this by shutting down the main install and visiting the queue manager of the alt install, you should have mail in there that will be delivered when you the main install comes back online. It’s automatic but not instant, wait up to 20 minutes for this to happen automatically.

The domain also needs MX records for both the main and alt installs of mailcow.