I want a high-level test that ensures that both incoming and outgoing email services are operating normally. I've achieved this by writing a python script which does this:
- Send a message with a unique hash through my mail server to email@example.com
- The gmail account is configured to auto-reply back to the same address and then delete the message.
- My script polls IMAP until it finds an email with the correct hash sitting in its inbox, or times out.
- It reports the elapsed time to my monitoring software (Zabbix)
My question: Is gmail the best third-party to use? Should I add a couple others as well such as hotmail and yahoo? Is there anyone more official that will auto-reply to these sorts of "mail pings"? Any other recommendations for this type of test?