Open Source Proxy

We currently use Linux as our router and have recently replaced our PIX firewall with another Linux box for that. We had an application that worked with the PIX to monitor employee internet usage and need to replicate that web based monitoring function so managers can easily view it.

We set up a proxy on Linux and it worked well. The problem is that we use Snort and Sguil for IDS and alerts. If everything is coming from the proxy we can’t tell where the traffic is coming from in Snort. Does anyone know a good Linux web based monitoring application that would meet our needs?