4
votes
How to restrict based on combined usage of sender email and client ip address in postfix?
Use a policy service. You can implement your own, or use some ready made one, I had some experience with postfwd and as I can recall its ruleset capabilities enable you to express such a requirement ...
- 11.9k
3
votes
What is difference between using smtp vs relay transport type in postfix?
relay tells postfix to deliver emails via a specific mailserver. You can see it as a simplified and faster delivery protocols, which does not obey to things as MX priority specifications.
smtp ...
- 49k
1
vote
What is difference between using smtp vs relay transport type in postfix?
When the transport is relay, Postfix will not send to the backup MX. This can be used on said backup MX, to avoid loops to itself.
In general, I would not use fallback MX BTW. They are often targetted ...
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