[Exim] Use of sender_reject_recipients not acting like I exp…

Hello -

In my exim configuration, I'm trying to reject a certain external sender from being able to send mail into our system (mail bomb issue). Sender_reject_recipients is what I want, I think, however, it's not acting like I expect it to. I added the following line to my exim.conf file:

sender_reject_recipients= Jhn1975pv@???

Now, according to the docs, this should result in a 550 after RCPT, indicating mail refused. However, in my configuration, it's resulting in this:

mail from: Jhn1975pv@???
421 Unexpected failure, please try later

When I use the mail from command, and that as the source address, it's throwing up a 421 error, and I can see in the log file that it's rejecting:

2002-08-27 15:23:22 recipients refused from <Jhn1975pv@???> H=12-229-81-142.client.attbi.com (test) [12.229.81.142]


I do not want a 4xx error, since that's a temporary failure. I want a 5xx response, which is what I understood it should provide. Anyone got any ideas?

Thanks for the help!

Jeremy
Netgarage.net