Hi Forum !
I have some understanding problems with ipforward and the meaning of routing .
I build up a test network with a gateway with 2 interface cards and different network ip's ,activate the ipforwarding ( echo >1 ....)so that the traffic behind the gateway host can reach the extern interface card. That seems to work ( ping from the local network to the extern card of the gateway).
The Ping to the next router ( its of course in the same network like the extern interface card of the gateway doesn't work.
Also the ping to the local interface of the gateway card from the router doesn't work.
router -> extern card-gateway- local card -> local net
192.168.1.10 ->192.168.1.1 gateway 192.168.2.1 -> 192.168.2.2
my meaning of ipforwarding is that every trafic to one interface would be redirect to the other interface , that should be possible in both ways or? that is simple routing ?
why cant i reach from the extern router with ping the client host behind the gateway??
thx for your answers

I was dealing with the same thing. I had a test environment set up and I thought everything was correct... but I couldn't ping through my "Linux Router". I did have everything set up correctly. The problem was on the router itself. I had to add an entry to tell it how to get back to the machine that sent the ping in the first place.
For my test I had just put a laptop on the other side of my firewall/router. So all I had to do on it was to set up a static route to the inside box pointing it to the firewall/router box as the gateway.

I hope this helps... When I found this out the first time I smacked my head and yelled STUPID STUPID!

I hope you will refrain from such self abuse.

Merry Christmas

Paul

thx for your post,
on the client maschine i added a static entry with the internal interface card of the firewall GW as the default entry,
doesn't help

merry xmas
breezer

When you say client machine are you talking about the "inside" machine?
Paul

yes i mean the "inside" hosts