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.

2023年12月13日 · Milter is set of API that provides an interface for third-party software to validate and modify messages ...

2016年6月11日 · 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 ...

2018年12月28日 · 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.

2022年10月17日 · The only conditional milter invocation that is preset in Postfix is checking the source IP address. However, by splitting the pipelines for the "reception" path and the "submission" path you can make this possible. I'd recommend to do this regardless of milter settings, because such setup is much easier to manage.

2023年6月9日 · If milter or Postfix (a policy service or whatever) rejects the command on some early stage (which often happens at RCPT TO because of smtpd_delay_reject is enabled by default), it won't bother to get a body from the peer and therefore won't pass it to the milter. But all commands that were exchanged prior to the rejection are passed to a milter.

2023年3月9日 · 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.

2017年4月28日 · In general, Its not very good idea to disable this simple anti-spam measure. Normal MTA would in response just repeat the message later, "as advised" (actually, because the reject code is 4xx, not final), and the successful delivery will be stored in the database and further emails in that direction will go without delay.

2022年4月7日 · Build a custom app that uses the Milter protocol and hook that up to Postfix with smtpd_milters. Of course, this will work. I can inspect the mail in my own app, then inject the header there. Seems over-engineering for a simple task like adding a header.

2018年5月24日 · I would like to set a milter using MIMEDefang on Ubuntu 16.04. I have an existing server using Sendmail 8.15.2-3. I installed MIMEDefang 2.78-1ubuntu1.1 (default package from apt). I configured my filter as I wanted and the service seems to be running. I can't seem to get sendmail to connect to the milter through.