[vchkpw] bandwidth monitoring

So is there anyway to monitor traffic on customers email virtualhosts? So i can keep track of the bandwidth their domain is using through qmail?

[vchkpw] qmail+vpopmail+mysql

Ok, I compiled vpopmail with mysql support. I want to store the open relay information in a mysql table. It looks like its saving all the ips into the table. So I compiled tcpserver with the mysql patch, made a /var/qmail/control/mysql file. Now how do I set tcpserver to use this file?