Russell Jones:
> For some reason, if a local user sends mail to another local user who
> doesn't exist, my Postfix installation doesn't seem to notify the sender
> of the error, nor deliver a bounce message to the sender.
...
> Sep 28 00:29:58 server2 postfix/smtpd[3447]: NOQUEUE: reject: RCPT from
> c-98-197-128-40.hsd1.tx.comcast.net[98.197.128.40]: 550 5.1.1
> <sadasd...@example.com>: Recipient address rejected: User unknown in
The 550 (and 5.1.1) response inform the SMTP client that the recipient
address is invalid.
If the SMTP client does not inform you, then that is a client problem.
These SMTP server responses are actually standardized.
If the exim server does not implement standard responses for invalid
recipient addresses, that is better discussed on an exim mailing
list.
Wietse
