Thank you for the guide. I manage a small setup in our building complex in India. The bandwidth terminates onto a linux box running proprietory bandwidth accounting package. This is connected to 80 odd houses via cascaded switches. I specifically want a transparent bridged caching proxy between the linux box and the internet users - So I connected the additional network card in the linux box into another box running a bridged squid proxy (followed the steps you described) on ubuntu 6.06 server; which in turn is connected to our distribution switch.
Internet<--->linux accounting/NAT<-->bridged squid<--->switch<---->80 houses
However the users are not able to visit sites like mail.yahoo.com, mail.google.com, rediffmail.com. etc.
there are no mail blocking rules defined and we do not specifically run any filtering or firewalling rules. Could this be an issue with the bridge? Everything works fine as soon as I eliminate the bridge from the network. All the installation on the bridge is default Ubuntu server with following additional packages:
squid doesnt have any mail blocking rules. I tried masquerading too on the bridged linux machine. All sites work fine (including email) but then my bandwidth accounting goes for a toss.
Thank you once again,