I successfully configure tproxy all the steps. (Patching Centos, Patching iptables, Building squid). And also WCCP configuration with L4 WCCPv2. When I trying check gre0 tunnel with any packet flow but don't found any request. My error showed.............. [root@heldas]# tcpdump -i gre0 tcpdump: WARNING: arptype 778 not supported by libpcap - falling back to cooked socket tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on gre0, link-type LINUX_SLL (Linux cooked), capture size 96 bytes ^C 0 packets captured 0 packets received by filter 0 packets dropped by kernel My iptables script is........... #/bin/bash /sbin/iptables -t mangle -N DIVERT /sbin/iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT /sbin/iptables -t mangle -A DIVERT -j MARK --set-mark 1 /sbin/iptables -t mangle -A DIVERT -j ACCEPT /sbin/iptables -t mangle -A PREROUTING -p tcp --dport 80 -j TPROXY --tproxy-mark 0x1/0x1 --on-port 3129 My Physical connectivity structure is .... Internet cloud to Cisco core router to Juniper firewall to Distributed Cisco router to Core Cisco switch to TPROXY Please give me a solution . Thanks Engr.Mohammad Monzur Alam Network & System Admin Grameen CyberNet Ltd. Dhaka, Bangladesh