Description

Creating an actual issue for tracking this.

I recently responded to a support question referencing the feature guidance in our docs: https://github.com/orgs/docker-mailserver/discussions/3605#discussioncomment-7418198

I've included a technical overview of the file in it's current state, while the file itself has plenty of information in comments and git blame should provide more from the original PR of mine that introduced them.

It would still be best to delay until the test suite can adopt compose.yaml + DNS approach for a proper relay test between DMS instances.

UPDATE:

• New reference comment for relay.sh context
• Jan 2024 PR providing another refactor iteration, with some relevant context links in the description (also see the revised relay.sh comments).

Additional issues discussing future improvements to consider supporting, such as recipient transport switching via transport_maps (3860 briefly mentions the sender equivalent variant as well):

• SMTP relaying depending of the recipient #1470 (comment) (EDIT: Nothing useful here that isn't already covered by the others AFAIK)
• relaying: mails are not relayed with implicit tls (465) / improve scripts & configuration #2601 (comment)
• question: Is the relay host support compatible with LDAP? #3860 (comment) (solid resource and discussion on the topic/details)

Related relay functionality issue to tackle after that: #3532