Viktor Dukhovni:
> I don't recall whether milter message content processing happens before
> or after canonical rewriting, Wietse might post a reminder. If milters
> go first, you'll need to do DKIM signing after the message first goes
> through a null content filter (directly back into Postfix on a different
> port, with nothing in the middle), with milters only on the far side and
> the canonical rewrites on the near side.
Postfix rewrites headers and envelopes before storing the message
in a queue file. Then, Milters can make changes, where each Milter
sees the result of changes made by its predecessor.
Wietse
