There won't be any visual indication that it's working, but you can probably look in the user change log to see users being switched to "Email invalid (bounced)".
They could already be flagged as email bounced, or maybe that status isn't logged. I'm not sure, I pipe the bounce handling through the core XF bounce handler.
Actually I just realized when I saw the checkbox for automated that my server is on AWS, which blocks 25 by default. Any reason you need to use 25 to send email? Isn't that just the default port for receiving SMTP?
Also, is there a way to test this and report it back to the user - me? Right now, there's no way at all to know if its working and/or why it isn't.
The reason why port 25 is necessary is because the feature opens a connection to the remote mail server as if it is going to send email, and listens for the response when your server says “I want to prepare sending an email to test@example.com”.
There is no progress info as it happens in the background, same as all XF cron tasks
But that doesn't need port 25 open on my server. The local server opens an ephemeral port (iirc, 40000+) and connects to the remote server on its port 25. So, I think your warning is technically incorrect. That's not really how TCP/IP works.
More importantly, the email validation doesn't seem to be working. How can I troubleshoot this?
When I was developing this feature and testing it @ this site, port 25 had to be open. The first point of troubleshooting is ensuring port 25 is open. If that’s not possible for you, you may not be able to use this feature.
While I can connect out on port 25 on my server, I can assure you that isn't actually a requirement. Outgoing ports are ephemeral. They are not tied one to one to the port they are connecting to.
It happens like this: randomlocalserverport:49652 connects to smtp.gmail.com:25
It's not localserverport:25 connects to smtp.gmail.com:25
And fwiw, its all SSL/TLS secured these days, so while it could connect to port 25, most don't.
Maybe this does a better job of explaining the connection process?
I know these are three questions, but I put them together because I think one connects with the other. I understand that when you want to send an email it's done using the SMTP protocol. Now port 2...