docs: add submissions DNS record for autodiscovery

Add the submissions autodiscovery SRV DNS record for implicit TLS in
SMTP (submission) connections according to
[RFC 8314](https://www.rfc-editor.org/rfc/rfc8314#section-5.1).
This commit is contained in:
Mynacol 2023-05-29 15:09:08 +02:00
parent 1bcfcf786b
commit 7e09d8f537

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@ -4,13 +4,14 @@ Autodiscovery
`RFC6186 <https://www.rfc-editor.org/rfc/rfc6186>`_ allows supporting email clients to automatically discover SMTP / IMAP addresses
of the mailserver. For that, the following records are required:
================ ==== ==== ======== ====== ==== =================
Record TTL Type Priority Weight Port Value
================ ==== ==== ======== ====== ==== =================
_submission._tcp 3600 SRV 5 0 587 mail.example.com.
_imap._tcp 3600 SRV 5 0 143 mail.example.com.
_imaps._tcp 3600 SRV 5 0 993 mail.example.com.
================ ==== ==== ======== ====== ==== =================
================= ==== ==== ======== ====== ==== =================
Record TTL Type Priority Weight Port Value
================= ==== ==== ======== ====== ==== =================
_submission._tcp 3600 SRV 5 0 587 mail.example.com.
_submissions._tcp 3600 SRV 5 0 465 mail.example.com.
_imap._tcp 3600 SRV 5 0 143 mail.example.com.
_imaps._tcp 3600 SRV 5 0 993 mail.example.com.
================= ==== ==== ======== ====== ==== =================
Please note that only a few MUAs currently implement this. For vendor-specific
discovery mechanisms `automx <https://github.com/rseichter/automx2>`_ can be used instead.