Quanah Gibson-Mount:
> We have a milter that examines emails and adds headers if it believes they
> are spam. However, it looks like 33% of the time, the headers that we've
> added to the email are stripped out by postfix before delivery, which ends
> up causing a lot of spam to get delivered. We've snooped the connection
> between postfix and the milter to verify that it is actually returning the
> spam headers:
If you use any software other than Postfix >= 2.3 to touch the
queue files, then you lose the headers that the Milter has added.
To debug:
- Use the Postfix HOLD action (access map, header/body_checks) to
freeze the mail in the queue.
- Then inspect the message (postcat -q queueid | less).
- Release the message with "postsuper -H queueid".
Repeat above procedure for each iteration of mail through a Postfix
MTA instance.
Use tcpdump to watch mail before and after Postfix.
Wietse
