configure squid3 as transparent proxy
There was a change in squid config option after version 2.6, replace that with :
http_port 3128 transparent
http_port 80 vhost
In squid versions 3.1 and up, the directive is: http_port 80 intercept. In versions 2.6 up to and not including 3.1, it's http_port 80 transparent. The intercept or transparent option tells squid to infer the proxy destination from the Host: header as with httpd_accel_uses_host_header.