I've just installed postfix on my debian system, so I have a default configuration, apart from the following values in /etc/postfix/main.cf:
myhostname = mydomain.com alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases mydestination = myhostname, localhost.localdomain, , localhost relayhost = mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 mailbox_size_limit = 0 recipient_delimiter = + inet_interfaces = all myorigin = mydomain.com relay_domains = mydomain.com
Every email I send to email@example.com bounces back with the mail server telling me:
This is the mail system at host mydomain.com. I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below. For further assistance, please send mail to postmaster. If you do so, please include this problem report. You can delete your own text from the attached returned message. The mail system <firstname.lastname@example.org>: mail for mydomain.com loops back to myself
How do I fix this problem?