[tproxy] problem with tproxy and iptables

[nantenaina Tianarivo]

Hello everybody,

I am tring to make tproxy work with our squid but I have a problem with
the iptable to redirect traffic to squid now.
I have compiled a linux kernel 2.6.22.18 patched with
tproxy-4.0.3-2.6.22. and iptable 1.3.8. For squid, i'am using Version
2.6.STABLE5.
I think my kernel is well compiled because I see all the tproxy module
loaded :

proxy:/usr/src/linux# lsmod | grep -i proxy
xt_tproxy               1984  0 
xt_TPROXY               1984  1 
iptable_tproxy          6468  2 xt_TPROXY
ip_tables              12420  2 iptable_filter,iptable_tproxy
x_tables               14564  5
ipt_LOG,xt_tcpudp,xt_tproxy,xt_TPROXY,ip_tables


My iptables rules is like this :

iptables -t tproxy -A PREROUTING -p tcp -m tcp  -i gre1 --dport 80 -j
LOG
iptables -t tproxy -A PREROUTING -p tcp -m tcp  -i gre1 --dport 80 -j
TPROXY --on-port 80

when I check it with tcpdump, I see traffic for http port on the gre1
interface

proxy:/usr/src/linux# tcpdump -n -i gre1
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 gre1, link-type LINUX_SLL (Linux cooked), capture size 96
bytes
13:10:51.437856 IP 62.56.240.17.3200 > 84.16.80.10.80: . ack 3247536657
win 2264 <nop,nop,timestamp 24199037 1582152>
13:10:51.492666 IP 62.56.240.17.3199 > 84.16.80.10.80: . ack 3204902926
win 3604 <nop,nop,timestamp 24199051 1582156>
13:10:51.523999 IP 62.56.240.17.3198 > 84.16.80.10.80: . ack 3189913679
win 16022 <nop,nop,timestamp 24199058 1582173>

when I check it on access.log of my squid, my requests are actually sent
to the squid.

But it is not the client ip which is sent to the Internet but the squid
box IP.

when I issue iptables-save -c command to check if there are traffic that
enter my iptables rule, the counter so zero traffic.

proxy:/usr/src/linux# iptables-save -t tproxy -c
# Generated by iptables-save v1.3.8 on Wed Feb 20 13:07:45 2008
*tproxy
:PREROUTING ACCEPT [128:11992]
[0:0] -A PREROUTING -i gre1 -p tcp -m tcp --dport 80 -j LOG 
[0:0] -A PREROUTING -i gre1 -p tcp -m tcp --dport 80 -j TPROXY --on-port
80 --on-ip 0.0.0.0 
COMMIT

even the LOG don't tell me anything about traffic in gre1 interfaces.

what I see in the log is this error that appear from time to time:

Feb 20 13:08:31 proxy squid[2353]: parseHttpRequest: NF
getsockopt(SO_ORIGINAL_DST) failed: (92) Protocol not available 
Feb 20 13:08:31 proxy squid[2353]: tproxy
ip=62.56.240.17,0x11f0383e,port=0 ERROR ASSIGN 

Can anyone tell me why my iptables don't redirect the traffic to the
squid?

Best Regards


Nantenaina Tianarivo
Sys Admin Blueline
-------------------
Today is what happened to yesterday.


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