OK, I don't use Exim (yet - I'm still waiting to get a proper virus scan solution set up first), but perhaps this might work:
<a href='http://mirrors.fourbatons.com/exim/exim-html-4.20/doc/html/FAQ_4.html#TOC148' target='_blank'>http://mirrors.fourbatons.com/exim/exim-ht...Q_4.html#TOC148</a>
<!--QuoteBegin-"FAQ_4.html#TOC148"+--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE
What is quickest way to set up Exim so any message sent to a non-existing user would bounce back with a different message, based on the name of non-existing user?A0416:
Place this router last, so that it catches any local addresses that are not otherwise handled:
driver = accept
transport = non_exist_reply
Then add the following transport to the transports section:
driver = autoreply
user = exim
to = $sender_address
subject = User does not exist
text = You sent mail to $local_part. That's not a valid user here. \
The subject was: $subject.
If you want to pick up a message from a file, you can use the file option (use file_expand if you want its contents expanded).[/quote]
Now, I realize that you have a catch-all set up, however, what would happen if you changed the spam-user alias to a non-existent account?
I'm not sure if Exim will take the alias to a bad account and not
let it fall through to the catch-all, but if this doesn't work, perhaps this may spark a different way of thinking on how to approach it...
I also found this PDF through Google:
<a href='http://ws.edu.isoc.org/workshops/2004/CEDIA/presentaciones/bc/correo/exim/AfNOG.pdf' target='_blank'>AfNOG 2003 The Exim Mail Transfer Agent (A brief introduction)</a>
(Google's "as HTML" link: <a href='http://18.104.22.168/search?q=cache:8ZJo1F0EfnEJ:ws.edu.isoc.org/workshops/2004/CEDIA/presentaciones/bc/correo/exim/AfNOG.pdf+exim+mail+bounce+%22/etc/aliases%22&hl=en&ct=clnk&cd=3&gl=us' target='_blank'>http://22.214.171.124/search?q=cache:8ZJo1...clnk&cd=3&gl=us</a>)
If nothing else, that document seemed to be a good reference... (But again, I'm not an advanced Exim user yet...
Another idea (from the same site):
<a href='http://mirrors.fourbatons.com/exim/exim-html-4.20/doc/html/FAQ_6.html#TOC185' target='_blank'>http://mirrors.fourbatons.com/exim/exim-ht...Q_6.html#TOC185</a>
<!--QuoteBegin-"FAQ_6.html#TOC185"+--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE
If a user's mailbox is over quota, is there a way for me to set it up so that the mail bounces to the sender and is not stored in the mail queue?A0605:
In the retry section of the configuration, put
That is, provide no retry timings for over quota errors. They will then bounce immediately. Alternatively, you can set up retries for a short time only, or use something like this:
*@your.dom.ain quota F,2h,15m; F,3d,1h
which bounces immediately if the user's mailbox hasn't been read for 7 days, but otherwise tries for up to 3 days after the first quota failure.[/quote]Set a quota for the spam-user account to somthing really
low, and just let everything from now on bounce due to a full account.
I, too, am interested in how this resolves, as I had intended on doing something similar once I'm completely set up.