SQUID TPROXY 모드가 동작을 안합니다..!!

제가 지금 squid를 사용해서 투명 프록시를 구성할려고 합니다
구성환경은
- squid 3.1.20
- Centos6.2
- 커널 2.6.32
- IPTABLE 1.4.7

squid
|
|
스위치-----Web server
|
|
PC

pc ip : 192.168.0.143
squid ip : 192.168.0.240(eth4)
web server ip: 192.168.0.197

이렇게 구성해서 모두 웹캐싱돼는것 까지는 전부 확인하였는데.

pc에서 squid를 거쳐 Web server에 접속한다음 웹서버 쪽에서
tcpdump 사용하여 80포트의 내용을 보니깐
PC의 IP가 찍혀있지 않고 squid가 있는 장비의 ip가 찍혀 있습니다.
그럼 tproxy 모드가 작동 하지 않는것 같은데...
어떤 것 때문에 그런지 모르겠습니다.
도와주세요.!!

squid.conf************************************
acl manager proto cache_object
acl localhost src 127.0.0.1/32 ::1
acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1

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 localnet src fc00::/7 # RFC 4193 local private network range
acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines

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 all
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports

http_access allow localnet
http_access allow localhost

http_port 3129 transparent
http_port 80 vhost

cache_dir ufs /usr/local/squid/var/cache 500 16 256
coredump_dir /usr/local/squid/var/cache

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

always_direct allow all
cache_effective_user squid
cache_effective_group squid
visible_hostname ns
visible_hostname ns
dns_nameservers 168.126.63.1

hierarchy_stoplist cgi-bin ?
acl QUERY urlpath_regex cgi-bin \? ## asp jsp php
cache deny QUERY
acl apache rep_header Server ^Apache
access_log /usr/local/squid/var/logs/access.log squid
cache_log /usr/local/squid/var/logs/cache.log
cache_store_log /usr/local/squid/var/logs/store.log
hosts_file /etc/hosts
*************************************************************

iptables 설정****************************************************
# Generated by iptables-save v1.4.7 on Wed Jul 18 11:51:57 2012
*nat
:PREROUTING ACCEPT [932:83166]
:POSTROUTING ACCEPT [188:12883]
:OUTPUT ACCEPT [188:12883]
-A PREROUTING -i eth4 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3129

COMMIT
# Completed on Wed Jul 18 11:51:57 2012
# Generated by iptables-save v1.4.7 on Wed Jul 18 11:51:57 2012
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [1251:418871]
-A INPUT -p tcp -m tcp --dport 3129 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 3128 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 8080 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 8080 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 3128 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 3129 -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p icmp -m icmp --icmp-type any -j ACCEPT
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -i lo -j ACCEPT
COMMIT
# Completed on Wed Jul 18 11:51:57 2012
# Generated by iptables-save v1.4.7 on Wed Jul 18 11:51:57 2012
*mangle
:PREROUTING ACCEPT [3686:805682]
:INPUT ACCEPT [3686:805682]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [2892:797404]
:POSTROUTING ACCEPT [2892:797404]
#-A PREROUTING -i eth4 -p tcp -m tcp --dport 80 -j TPROXY --on-port 3128 --on-ip 0.0.0.0 --tproxy-mark 0x1/0x1
-A PREROUTING -i eth4 -p tcp -m tcp --dport 80 -j TPROXY --on-port 3129 --on-ip 0.0.0.0 --tproxy-mark 0x1/0x1
-A PREROUTING -i eth4 -p tcp -m tcp --dport 80 -j TPROXY --on-port 3129 --on-ip 192.168.0.240 --tproxy-mark 0x1/0x1

COMMIT
# Completed on Wed Jul 18 11:51:57 2012