Public bug reported: At the moment the LMTP runner rejects mails to non-existing lists after the DATA stage. # telnet localhost 8024 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 mail.svr02.mucip.net Python LMTP runner 1.0 MAIL FROM: 250 Ok RCPT TO: 250 Ok DATA 354 End data with <CR><LF>.<CR><LF> Message-ID: as . 550 Requested action not taken: mailbox unavailable It should reject invalid addresses in the RCPT TO stage, this way it could easily be used with Postfix' feature "reject_unverified_recipient" to avoid accepting and then bouncing messages. ** Affects: mailman Importance: Undecided Status: New -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/982555 Title: LMTP should reject unknown lists in RCPT-stage To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/982555/+subscriptions