IPTables Forward chain confusion..

[dsr at tao.merseine.nu (Dan Ritter)]

On Fri, Mar 30, 2007 at 05:31:20PM -0400, Myrle Francis wrote:
> I screwing around trying to learn IPTables. I pretty good and understanding
> the INPUT & OUTPUT chains, and I'm manipulating then nicely. What I dont
> seem to grasp is the FORWARD chain & when it is used.
> 
> the scenario (the home network)
> I have dd-wrt (linux for your linksys)  installed on my router. my home
> network is just a single network and no subnets.
> so in this example the FORWARD chain never get used because... (and here is
> my guess) Forward is used to forward between subnets on my network (if I had
> any) or to my dmz.

Any time that you machine acts as a router, accepting packets
that are not destined for itself, FORWARD is invoked.

if /proc/sys/net/ipv4/ip_forward contains a 0, no forwarding
will occur. If it contains a 1, packets will be forwarded.

-dsr-

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