Major battle we must fight as hosting providers are spammers ruining our servers IP credibility. KloxoMR uses qmail-toaster, which is a very efficient MTA, it lacks a few features.
Major problem is sendmail. It can forge domain, to/from, the only thing that is a result... IP ban.
Sendmail limiter is a wrapper script which uses mysql to keep track of sendmail, and limit by hour, half day, and full day. You can even completely ban a client/user from sendmail.
Full logging abilities, even able to let you know which directory the script which is sending mail is at.
You can use for just limiting, just logging, or both.
Install is easy with my auto installer, you have a few things to do manually (mysql database, cron).
SSH:
cd /tmp
wget http://cc-server1.us/sendmail_wrapper.zip
unzip sendmail_wrapper.zip
Read sendmail-chrisf.txt, full instructions
Please report performance issues or bugs. I am developing other scripts to help manage the client settings, and a auto group script to increase group by days active.