ConfigServer Services
Server Management Services from Way to The Web Ltd

There are sound technical reasons that you should only use :fail: and not :blackhole: on a cPanel server running exim. We have conducted quite extensive testing to establish this configuration is best and outline the reasons here.

In general the two different settings both discard email not destined for a POP3 account, an alias or a catchall alias. However, the way email is discarded differs with the two methods quite starkly:

Here is a simple explanation of what happens during the SMTP conversation