The log correlator is an add-on for CanIt that lets you search the mail logs from within the CanIt web interface. It's actually a really nice feature because you can build up complex searches to find specific logs and it adds explanations for most log lines to help you understand them.
If you wish to install it, simply make sure you're running CanIt 9.2.8, or later, and run the following commands on the primary DB server:
apt-get update apt-get install canit-log-correlator canit-prepare-system service canit restart
and on all other machines in the CanIt cluster:
apt-get update apt-get install canit-log-correlator service canit restart
NOTE: Installing the log correlator changes the layout of the mail logs. Instead of going into /var/log/mail.log, they will go into /var/log/mail-daily/mail-YYYY-MM-DD.log