> When sending a mail to some @helpdesk.inria.fr address, postfix tries > to connect to helpdesk.inria.fr (which does not have a MX): > > Nov 21 15:43:26 joooj postfix/smtp[748304]: D1A104A9: > to=<[...]@helpdesk.inria.fr>, relay=none, delay=76462, delays=76431/0.1/30/0, > dsn=4.4.1, status=deferred (connect to helpdesk.inria.fr[128.93.128.88]:25: > Connection timed out) > > Some admin at Inria tells me that this is incorrect and that postfix > should connect to the MX of the parent domain (inria.fr) in such a > case.
See Simple Mail Transfer Protocol (SMTP), RFC 5321: https://datatracker.ietf.org/doc/html/rfc5321#section-5 "The lookup first attempts to locate an MX record associated with the name. If a CNAME record is found, the resulting name is processed as if it were the initial name. If a non-existent domain error is returned, this situation MUST be reported as an error. If a temporary error is returned, the message MUST be queued and retried later (see Section 4.5.4.1). If an empty list of MXs is returned, the address is treated as if it was associated with an implicit MX RR, with a preference of 0, pointing to that host." $ host -t mx helpdesk.inria.fr helpdesk.inria.fr is an alias for prod-symfonyu20-app.inria.fr. $ host -t mx prod-symfonyu20-app.inria.fr prod-symfonyu20-app.inria.fr has no MX record $ host prod-symfonyu20-app.inria.fr prod-symfonyu20-app.inria.fr has address 128.93.128.88 --> connect to 128.93.128.88 Best regards, Gerald _______________________________________________ Postfix-users mailing list -- postfix-users@postfix.org To unsubscribe send an email to postfix-users-le...@postfix.org
