topic Re: redirect the whole HTTP traffic using proxy in Operating System - Linux

redirect the whole HTTP traffic using proxy

'chris' — Sat, 30 Sep 2006 10:29:34 GMT

hi

howto redirect the whole HTTP traffic using proxy ?

I have tried using iptables:

iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination 192.168.0.5:3128

but it doesn't work !

this machine is a vpn gateway and should redirect the whole HTTP traffic to the proxy.

p.s
I don't have a transparent proxy.

greetings
chris

Re: redirect the whole HTTP traffic using proxy

Alexander Chuzhoy — Sat, 30 Sep 2006 12:29:50 GMT

I did it once with reverse proxy.
All http that comes to proxy is redirected to internal web server- below is the link to a guide:

http://www.visolve.com/squid/whitepapers/reverseproxy.php

Re: redirect the whole HTTP traffic using proxy

Steven E. Protter — Sat, 30 Sep 2006 14:03:41 GMT

Shalom Chris,

Often this mistake is made.

Before forwarding traffic, which is what your statement does, check the file /etc/sysctl.conf

It must have ipv4 forwarding set to yes.

Then try again, that alone may be the issue.

SEP

Re: redirect the whole HTTP traffic using proxy

Michal Toth — Wed, 04 Oct 2006 16:36:59 GMT

some distros do not reference ip_forwarding in sysctl,.. use cat cat /proc/sys/net/ipv4/ip_forward to get your current status,.. though if that is indeed a gateway, then it should be turned on

next you can do some debugging with logging packets:

iptables -t nat -A PREROUTING -p tcp --dport 80 -j LOG --log-prefix " (INC_HTTP)"
... DNAT line here ...
iptables -t nat -A POSTROUTING -p tcp --dport 80 -j LOG --log-prefix " (OUT_HTTP)"