redirect traffic

tim_24 · 05-26-2007, 01:27 PM

Hi all,
I have a linux system (2.4), 1 nic.
I have a user level http proxy program that's running and listens on port 9999.

I want to proxy web traffic (still, from same system) without manually config browser to point to my local proxy:9999.

Is it possible to do it with iptable rules?
If so, please give me some details.

If not, what are other solutions for this?

Thanks a lot for any help
Tim

osor · 05-26-2007, 11:36 PM

Have you tried something like this:

Code:

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 9999

(that way, any traffic destined for tcp port 80 will be redirected to port 9999)

P.S., there are many threads pertaining to this question, and googling is also helpful.

tim_24 · 05-27-2007, 03:26 AM

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 9999

I think this rule is for inbound traffic, right?
May be my question was not clear.
I want to redirect outbound traffic from local browser to my program
(same system).

Thanks again for any help.

osor · 05-27-2007, 12:33 PM

Quote:

Originally Posted by tim_24

I think this rule is for inbound traffic

What makes you think that?

Take some time to read up (

) on transparent proxying.

tim_24 · 05-28-2007, 12:39 AM

Hi 0sor,
I did read it. May be I'm too dumb or something.

I even try it here on my linux machine by these steps:

1>Add rule: iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 9999

2>running my app listen on tcp port 9999
3>open browser and go to www.yahoo.com

my app doesn't get any connection at all.

Please clarify.
Thanks again.