As of recently a server of ours is being flooded with an additional 300000 + messages a day. The exim RBL acls are doing their job of checking the RBLs and preventing the messages from getting further. However I believe the overhead of the RBL checks is causing the servers load to be sky high (over 30) Shutting down exim load goes away. So the load I believe has to be caused by exim.
Interesting thing is that these junk messages are all from RBL'ed IPs. The sender always changes however one thing that is consistent is the first 3 letters of the email address. For instance the messages always come from abc*@* where abc is always the same.
Anyhow I was recommended to use the following ACL to filter out and reject messages from abc*@*
deny senders = /etc/exim/sender_reject.list
I put abc*@* in the sender_reject.list
However all mail then was rejected.
Does anyone else have any suggestions on this issue?