Jesse Osby:
> But it only works when I send to a local address that gets forwarded to an
> external one via /etc/aliases. Here's what I've found:
>
sender_canonical_maps can rewrite the sender in:
- mail submitted with the Postfix sendmail command
- mail received via the SMTP server
- mail that is internally forwared (via /etc/aliases or ~/.forward)
- and perhaps mail that is internally generated by notify_classes.
But it is possible to disable this with receive_override_options.
So I suggest that you look for receive_override_options settings
in main.cf and master.cf.
The receive_override_options is used to prevent repeated
adddress mapping before and after a content filter.
Wietse