Transparent Proxy with squid

squid.conf:

* httpd_accel_host virtual
* httpd_accel_port 80
* httpd_accel_with_proxy on
* httpd_accel_uses_host_header on
* acl our_networks src xx.xx.xx.xx yy.yy.yy.0/24
//xx.xx.xx.xx -> ip for outgoing interface
//yy.yy.yy.0 -> internal IP
* http_access allow our_networks
* http_access allow localhost
* http_access deny all


Script for iptables:

// eth0 -> internal NIC
// eth1 -> outgoing NIC
iptables --flush # Flush all the rules in filter and nat tables
iptables --table nat --flush
iptables --delete-chain
iptables --table nat --delete-chain
iptables --table nat --append POSTROUTING --out-interface eth1 -j MASQUERADE
iptables --append FORWARD --in-interface eth0 -j ACCEPT
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 3128