This is a very simple script for email delivery checking/monitoring. It sends a test email with a random subject to the configured recipient address using a configured SMTP configuration (e.g., SMTP on localhost).
Afterwards, it tries to retrieve that email using IMAP authenticating on the remote mail server. When it has successfully fetched the email.
The script’s purpose is to be executed on a different server than the tested mailhost.
This way, it can check whether external email delivery works as intended.
Running it directly on the mailhost can cause some errors to go unnoticed, i.e., if only external email submission is affected.
This script was modified to take an additional external smtp-server and recipient so it may be run on the server under test with the caveat that only some error conditions may be reported.
To deploy this script, adapt the config.py.example as config.py and register a cron to periodically call this script depending on your requirements, e.g., every 15 minutes.