setup squid on redhat box. the redhat box should have 2 NICs. One to connect to modem and one to the switch which is connected to ur LAN. then set iptables like this:
Code:
iptables -t nat -A PREROUTING -s 192.168.0.0/24 -p tcp --dport 80 -j REDIRECT --to-port 3128
that is if ur LAN is 192.168.0.x. U should also read the transparent-proxy mini HOWTO at TLDP.