Nov 26, 2009 · The main difference is that Milter happens pre-queue, i.e. before Postfix accepts the mail. Content filtering happens post-queue. It depends on the circumstances and the resources you have available. In general, post-queue content filtering in my experience is less resource intensive. Postfix handles the SMTP transactions, queue's the mail and this can happen relatively quickly and painlessly ...

Mar 9, 2023 · I suspect that your most pressing configuration issue is that you added the spamassassin daemon (that normally talks to programs like spamc or spamass-milter) to the Postfix interface that speaks the Sendmail Milter protocol.

Oct 17, 2022 · Then, your extra milter will only be processing authenticated submissions - because only those are accepted at the port the milter is attached to. In postfix, you can easily do so by attaching -o options to the relevant service definitions in the master.cf file.

Jun 9, 2023 · I've configured postfix to use a milter. Unfortunately, it seems that all email goes through the milter, even email that is rejected with "User unknown" messages or email rejected by the

Dec 4, 2023 · The milter interface allows you to parse, and selectively remove or rewrite arbitrary headers, or message body (parts). However, editing is possibly better done in post-queue processing, past address-rewriting and multi-recipient pitfalls.

Jul 21, 2017 · I'm on Ubuntu 16 LTS, trying to sign mail with opendkim and I'm getting: $ tail /var/log/mail.err ... Milter (opendkim): error connecting to filter: Connection ...

Jun 11, 2016 · I'm trying to get spamassassin working on Ubuntu 16.04 with postfix. When receiving mail, I get messages similar to the following in my logs: Jun 11 14:29:47 myhost postfix/smtpd[2387]: connect ...

Dec 28, 2018 · Milter: from=<[email protected]> reject=451 4.3.2 Please try again later We are checking milter.log but we don't get any conection from the other MTA. Besides, milter filters are only for distribution lists and the addresses showing out in the errors are user names, not distributions lists.

Apr 28, 2017 · Are you sure that OpenDKIM is the source of the problem? The "Try again later" message could very well be caused by Rspamd's greylisting feature, if you are using it. If you have Rspamd enabled, I’m 99% sure that greylisting is responsible for the 4.7.1 Service Unavailable - Try again later message. To disable greylisting in Rspamd, follow these steps: Open (or create) the configuration file ...

Apr 7, 2022 · Postfix parameters specifying lookup tables are just comma/space separated lists of type:name references, so there is an easy way to stack them. I was going to suggest using that in conjunction with always_add_missing_headers=yes, but I am uncertain whether that is a complete answer (as documentation in some places sounds like cleanup is adding missing headers only once after header_checks ...