Agent WranglersUnsubscribe and bounces Required
Accept mail at postmaster and abuse
Accept mail for postmaster@ and abuse@ on every domain you send from, and route it to a person who reads it.
How to do it
RFC 5321 requires every mail domain to accept mail for postmaster, in any letter case. RFC 2142 names abuse for reports of spam and misuse. Other servers send delivery problems and complaints there. Never filter these addresses as spam, and never let them bounce.
How to check
Send a test message to postmaster@example.com and abuse@example.com from an outside account. Both arrive in a monitored mailbox, and neither bounces.
For agents: if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in Based on the Agent Wranglers email playbook: https://agentwranglers.se/playbook/email/unsubscribe-and-bounces/postmaster-abuse.