I just checked, and it looks like RP filter is disabled on the Squid box. root@squidproxy:~# cat /proc/sys/net/ipv4/conf/all/rp_filter 0 root@squidproxy:~# cat /proc/sys/net/ipv4/conf/eth0/rp_filter 0 root@squidproxy:~# cat /proc/sys/net/ipv4/conf/lo/rp_filter 0 root@squidproxy:~# cat /proc/sys/net/ipv4/conf/default/rp_filter 0 -- View this message in context: http://squid-web-proxy-cache.1019090.n4.nabble.com/Squid-3-3-Intercept-Proxy-Traffic-routing-to-Squid-Box-Now-what-tp4660046p4660067.html Sent from the Squid - Users mailing list archive at Nabble.com.