Reporting On IP Masquerading Usage?

C0sm1c asks: "I administer a Linux box on my company's LAN that provides all Internet connectivity to staff using Linux IP Masquerading (as well as squid, named etc...). What I need now is a means to report on the Internet usage of machines being masqueraded, and provide reports in both real time and periodic summaries of network usage. These reports will be available for anyone to view, to reduce the misuse of the Internet connection at work as well as usage stats. I've looked at MRTG but it doesn't appear to know about Masqueraded traffic, or provide a means to show the top ten users of the Internet etc... and a breakdown of the protocols used (like amount of ftp, telnet, ICQ traffic). This seems to me to be a fairly common ask, is there an open source package that can provide all this with HTML based reporting?"