mreport is a simple C program that processes
/var/log/maillog (or whatever you specify as
the mail log). What is probably its only
limitation is that it can only process sendmail
logs. Nevertheless, it makes very nice summaries
of the mail logs, and can be useful for system
administrators that are tired of poring through
sendmail's copious logs trying to figure out
how well their mail server configuration is
holding up.