How do i port forward in iptables?

Question

I have created a new interface eth0:1 and assigned ip address using DHCP server. Now, i want my applications to use the internet of this new interface created. I am doing this because in out Institute, we have bandwidth limit on each IP address.

Now, i want to do something like:

if I try to use localhost:3129 as a proxy, this traffic gets forwarded to eth0:1 interface. How can I do so?

So that by using localhost:3129, i can actually use my interface eth0:1.. I only figured out this method because not many applications today have an option of binding to a particular interface.

Answer 1

iptables -t nat -I PREROUTING -p tcp --dport 3129 -d 1.2.3.4 -j REDIRECT --to-port 3128

But your statement that "not many applications today have an option of binding to a particular interface" does not match with my experience -- most applications I have deployed have an option to do this.

Answer 2

Here's some links that might be able to help out your request.

http://www.hackorama.com/network/portfwd.shtml http://www.debian-administration.org/articles/73 http://www.linuxforums.org/forum/linux-networking/30261-iptables-port-forwarding.html

Hope this helps!