The one thing about computing is that it is so literal. I wish programmers would add some intelligence into their products, yet allow us to override it.
In this case for a customer a user attempted to forward an email from her old email account to the one I set up on their very own email server. It worked great, but I didn’t have the proxmox mail gateway put in place.
When I set this up I immediately got a message from her telling me that the forwarded message didn’t go through to the new server, that it had rejected it and sent her a reject message.
She forwarded me the rejected email and I looked it over and found that it said SPF failure.
I checked her registrar’s DNS records and it had the appropriate SPF record. I compared it to my main email set up and they were duplicates.
The email contained a reference to some domain that was not familiar to me.
My natural inclination is to resolve the issue and learn from resolving it. In this case, as the gateway is in place I needed to resolve it quickly. With the proxmox mail gateway the fastest way is to blow away the container running the gateway and redo it. I did this.
After doing this I did a forwarding email test myself and all went well. At that point I think I understood the problem. In the mail gateway configuration you set a transport, port, and relay. I believe I set the transport to forward to itself instead of the actual email server. Because the server itself isn’t allowed to send emails well…. I’m not 100% sure so we’ll see.
The weird DNS in the rejection notice of the email was that the proxmox main environment had an incorrect domain name. I corrected that. If I get any more rejects I should see the proper info in the response text.