Need a recommendation for Log File Analysis

[Bill Schmitt (SW)]

I'm looking for an application to run on our FreeBSD 4.9 server that 
will allow some mining of data from our mail logs (Postfix). For 
example, what ip's are rejected because they are incorrectly formatted 
or what domains are not providing reverse dns entries (which we reject). 
Being able to mine down looking for repeated mailings to invalid 
mailboxes would be nice.

Looking at the information in the ports doesn't seem to indicate a 
specific application that does these things. Does this kind of animal exist?