LinuxQuestions.org - linux as router/gateway/firewall to dsl-router

Hello,

I set up a network like this:

dsl_(speedtouch-router)-----linux_router-----switch-----box

eth0 dsl_router int 10.0.0.138
eth1 linux_router int 10.0.0.161 to switch
eth0 linux_router ext 10.0.0.151 to dsl_router gateway 10.0.0.138
eth0 box 10.0.0.150 gateway 10.0.0.161
netmasks 255.255.255.0

I statically assigned ip-addresses to the box and the linux router
both it´s networkcards.
When I ping from box to linux router (10.0.0.151 and 10.0.0.161) both
of them work.
Pinging from linux_router to box is ok.
But only when I use:
´ifconfig eth1 down ifconfig eth0´ up the linux_router is able to ping to dsl_router (or otherwise to linux box).
I can bring up both interfaces, but I am only able to ping through one of them depending on which one I bring up first.

With my linux box I can reach both cards on linux_router, but not my dsl_router.

I run Suse 10.0 on linux_router, within yast configuration I configured routing with default gateway 10.0.0.161 (this is correct I think for it is the gateway for boxes), ip-forwarding on

For now I used the speedtouch for routing, I figured out I can upload a template for the
speedtouch so it acts as bidged ethernet device.

But with both of them routing I can´t connect a box to the speedtouch, it must be possible
I think, does anyone has an idea?

Is two routers not wise to choose, or doesn´t matter? (hard configuration or so)

Should I have a different network e.g. 10.0.1.x (or so) for int network?

My main questions: How to give the box internet through the linux_router and through the speedtouch dsl_router?

Are there important configurations wich I could have forgotten?

I stopped the firewall and tried the ping´s again but still didn´t work. Or does the firewall have to run with some adapted configuration?

Thanks!