[plug] IP Chains

[Michael Hunt]

> Michael Hunt wrote:
> >
> <snip>
> > Mikes Quick and dirty quide to IP masquerading
> >
> > 1. Turn on IP forwarding. You can do this through most distro's control
> > panel app (at least under RedHat) or by echo an 1 to the
> relevant proc file
> > (the name surpasses me at the moment).
>
> <snip>
>
> What is IP forwarding?

Ip frowarding basically means routing. Look at it this way

My Machine 192.168.1.11 (workstation) sends a packet to the internet.
According to the routing tables on my machine this goes to the default
gateway (192.168.1.254 eth0:0). My linux box has ip masq, ip forwarding and
ip chains installed so what happens next is this:

Routing table is looked up on Linux box and it sees that the default gateway
is my ppp adapter. Because my box has the above on it forwards the packet on
to the internet (masking it as a routable IP address using the IP off my ppp
adapter). It also filters any outgoing and incoming packets to see if they
might my ip chain rules.

Michael Hunt