Posted by Ian Marshall, Last modified by Ian Marshall on 06 June 2014 04:40 PM
You should limit the number of servers you choose to query for RBL processing since having too many servers queried can have a detrimental effect on your IceWarp server performance.
Limiting to 2-3 is the recommended number. Each server should be queried at least once for each incoming message, adding overhead to the processing.
There are two places these Blackhole Lists settings can be enabled.
Check these settings under Anti-Spam>SpamAssassin>RBL tab & Mail>Security>DNS tab.
(These instructions are for IceWarp 11 but older versions should be similar.)