I have a weird issue with my postfix installation, also I'm having troubles to debug it because I'm new to the topic. When I check my log lines:
postfix/smtp: A929510E76D9: to=<firstname.lastname@example.org>, relay=none, delay=78304, delays=78274/0/30/0, dsn=4.4.1, status=deferred (connect to mail.domain.com[220.127.116.11]:25: Connection timed out)
First of all our email addresses are all in the form email@example.com, so I don't really get why some process is sending emails to firstname.lastname@example.org which is then trying to connect on itself on port 25 and fails.
Other than that everything works correctly apparently. How can I understand who is issuing this request and for which reason the mailserver tries to connect to itself?