Mail-receiver relay access denied

Trying hard to enable replies by email using the mail-receiver container. I consistently get errors:

NOQUEUE: reject: RCPT from ... 454 4.7.1 <...>: Relay access denied

Why is this? How can I get into the mail-receiver container and examine the postfix config and debug it? I have disabled the postfix server on the system on which this is running, because of clash with port 25. Is that wrong?

I am reasonably sure DNS MX records are right, and this happens from any server sending mail inbound, I am using Amazon SES for outbound in the app container and that works fine.

I am a Discourse newbie and I dont know how to debug the ecosystem. I am an expert in postfix, but I don’t know how to configure it in this containerized universe.

First thing first, if You already have a postfix instance running, You don’t really need the mail receiver container.

You can configure postfix as an email receiver for the replies email and configure discourse to poll that email.

This #howto from 2014 shall give you enough idea to get started and I assume you can figure postfix on your own.

I don’t agree with this at all, the benefit of the mail-receiver is that emails are pushed via the API, rather than polled. There’s a significant difference in the time taken for email to arrive in Discourse using the mail-receiver (minutes versus seconds).

There’s also a huge difference in simplicity in configuration, mail-receiver requires three lines of a yml file be updated, the postfix OOBE requires… more.

That error implies the mail domains don’t match.

As you’re obfuscating parts of the message we can’t easily troubleshoot this for you.

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If you’re getting any mail delivered as you expect, then this implies that someone is trying to use your mail server to deliver mail to some other domain. If, for example, someone pointed their MX record to your IP address. Or, and I’ve never heard of this :wink: , someone was trying to nefariously have your mail server deliver unwanted mail.

Are all of these errors from the same IP? Can you see in the logs what domain they the errant messages are intended for?

The easiest thing to do is to ignore it.

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I had this issue on a previously working mail-receiver which I’d made some changes to. I had thought I’d rebuild the container but clearly something hadn’t gone right as I got multiple ’ Relay access denied’ errors for all recipients. DNS was correctly configured.

In the end a good old git pull and launcher rebuild mail-receiver fixed it. Just posting this in case it works for anyone else.