Hello, I'm trying to get TProxy 4.1 to work as outlined here: http://wiki.squid-cache.org/Features/Tproxy4 namely under Ubuntu 9.04 stable/testing mix with the following: linux-image-2.6.28-11-server 2.6.28-11.42 iptables 1.4.3.2-2ubuntu1 squid-3.1.0.7.tar.bz2 from original sources Squid has been built this way: $ /usr/local/squid/sbin/squid -v Squid Cache: Version 3.1.0.7 configure options: '--enable-linux-netfilter' --with-squid=/home/guessed/squid-3.1.0.7 --enable-ltdl-convenience (myself I only gave it --enable-linux-netfilter) squid.conf is pretty much whatever 'make install' created, with my changes given at the end, after the blank line: acl manager proto cache_object acl localhost src 127.0.0.1/32 acl to_localhost dst 127.0.0.0/8 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network acl localnet src 172.16.0.0/12 # RFC1918 possible internal network acl localnet src 192.168.0.0/16 # RFC1918 possible internal network acl SSL_ports port 443 acl Safe_ports port 80 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl Safe_ports port 70 # gopher acl Safe_ports port 210 # wais acl Safe_ports port 1025-65535 # unregistered ports acl Safe_ports port 280 # http-mgmt acl Safe_ports port 488 # gss-http acl Safe_ports port 591 # filemaker acl Safe_ports port 777 # multiling http acl CONNECT method CONNECT http_access allow manager localhost http_access deny manager http_access deny !Safe_ports http_access deny CONNECT !SSL_ports http_access allow localnet http_access deny all http_port 3128 hierarchy_stoplist cgi-bin ? refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern . 0 20% 4320 coredump_dir /usr/local/squid/var/cache cache_dir ufs /usr/local/squid/var/cache 100 16 256 cache_mem 16 MB http_port 3129 tproxy visible_hostname tproxy Then I did: iptables -t mangle -N DIVERT iptables -t mangle -A DIVERT -j MARK --set-mark 1 iptables -t mangle -A DIVERT -j ACCEPT #Use DIVERT to prevent existing connections going through TPROXY twice: iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT #Mark all other (new) packets and use TPROXY to pass into Squid: iptables -t mangle -A PREROUTING -p tcp --dport 80 -j TPROXY --tproxy-mark 0x1/0x1 --on-port 3129 ip rule add fwmark 1 lookup 100 ip route add local 0.0.0.0/0 dev lo table 100 #On each boot startup set: echo 1 > /proc/sys/net/ipv4/ip_forward ran squid -z and launched squid. My topology: desktop where I sit: one link has address 192.168.0.1/24, the other to the Internet Squid box: one link: 192.168.0.184/24 (bridged VMware interface on the same box as desktop), the other link is custom VMware interface 192.168.1.1/24 The "client" box: single interface 192.168.1.2/24 So, the squid box is directly connected to the outside on the one side, and to the client on the other. My desktop's routing knows to reach the client through the Squid box, and vice versa, so the port 80 traffic under consideration flows through the Squid box in both ways. Now, after I do this on the "client": $ telnet 192.168.0.1 80 GET / HTTP/1.0 (correct webpage output) Connection closed by foreign host. Nevertheless, in 192.168.0.1's webserver's logs I can see 192.168.0.184 connecting, not the TProxied 192.168.1.2, as if working under the plain ole interception proxying I've been trying to get rid of! Why?! Counters on the Squid box do get bumped: $ sudo iptables -t mangle -L -v -n Chain PREROUTING (policy ACCEPT 163 packets, 21851 bytes) pkts bytes target prot opt in out source destination 2274 214K DIVERT tcp -- * * 0.0.0.0/0 0.0.0.0/0 socket 16 920 TPROXY tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 TPROXY redirect 0.0.0.0:3129 mark 0x1/0x1 ... Chain DIVERT (1 references) pkts bytes target prot opt in out source destination 2274 214K MARK all -- * * 0.0.0.0/0 0.0.0.0/0 MARK xset 0x1/0xffffffff 2274 214K ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 Thanks for any tips.