I have three computers, A, B, and C. A and B are connected through ppp over a null modem cable. B and C are on an Ethernet network. A is address 10.0.0.2, B is 10.0.0.1 on the ppp network and 192.168.1.200 on the Ethernet. C is 192.168.1.220. A and B run Linux, C runs Windows. I am trying to route packates from A to C via B, but `ping 192.168.1.220' from A never gets a response, and traceroute doesn't find a route. Here is my routing configuration (from `ip route'):
C has its default gateway set to 192.168.1.200.

Anyone know what's wrong with my configuration?

You'll need to add a route on 'A' for 192.168.1.0/24 via 10.0.0.2, you'll also need to ensure that 'B' is correctly configured to forward traffic between interfaces

cheers

Did you mean via 10.0.0.1 (address of B).
I tried adding that route, but it didn't help. I would thing that the default route should be enough anyway.

What did you mean to set up routing between interfaces? Is there anything besides the ip routing tables that must be configured?

You've listed the address of B as 10.0.0.2 not 10.0.0.1

The default route will not be enough.

To set up ip forwarding on B you will need to edit /etc/sysctl.conf and look for these lines:

.. change from 0 to 1 to enable forwarding

Then run 'sysctl -p /etc/sysctl.conf' to activate the changes

Thanks!

The adjustment to /etc/sysctl.conf (or rather the addition of such) fixed the problem.

I see where you got 10.0.0.2 for B. That was the routing table for B, no the address.

By the way, can you edit this setting using the /sys filesystem?

I can't say that I've tried... usually turn on ip forwarding temporarily using '/proc/sys/net/ipv4/ip_forward'