Wietse Venema:
What is the difference with final delivery to Dovecot?
There is nothing special about the fact that I'm doing final delivery to Dovecot, but it is what made me notice the problem. I just personally consider it invalid for an envelope sender address to contain a UTF BOM, and I wish Postfix would allow me to address that without resulting to quite custom configuration with PCRE matching. If it is actually technically valid to have a UTF BOM right in the middle of the envelope sender, then I agree that Postfix should continue behaving as it does, but it still would be nice to have an easy configuration option to affect that behavior, as I find it highly unlikely that there's a legitimate use case for it.
It seems to me that Dovecot's behavior of not considering the envelope sender during the recipient check is valid, as the envelope sender is outside the scope of checking whether a recipient is valid, but it would of course be very nice if Postfix could work together with Dovecot's LMTP to do a more thorough check not only limited to the recipient; maybe it can, as I'm no expert.
