how to setup router on linux as a open firewall
 

Hi anybody,


I want to set up a router on linux for NIST Net testing. The router should allow all traffic without any filters between interfaces eth0 and eth1. That means open firewall.

I have been trying to achieve this, but I couldn’t succeed. I could ping in one direction but not in other direction.

Could anybody help me in resolving this problem?
I want step by step procedure to setup open firewall router.

Thanks,
Thiru

What kind of IPs are used by networks connected to eth0 and eth1? Are they local in one of the networks, local in both or both global?

thanks for the reply.

local in both.

Here is the picture:

GW-------SW-------------[eth0 linux box with redhat 9.0 eth1]--------client pc

Eth0: 192.168.10.40 with 192.165.10.0 network
Router/GW: 192.168.10.1

Eth1: 192.168.20.1 with 192.168.20.0 network

Client PC: 192.168.20.25


thanks,
Thiru

So I understand that RH box has 192.168.10.x subnet set to be sent to eth0 and 192.168.20.x to eth1.
How have you set the GW on client PC? It should have a gateway in the same subnet it's in, so the geteway for it should be 192.168.20.1 (RH machine).

yes, I do.

The client PC has GW set to 192.168.20.1.

-thanks

Hello anybody,


Any idea?

-Thiru

So how does the routing table on RH machine look like?

thanks for the reply.

here is the route command output:


Here is “route” command output:

192.168.20.0 * 255.255.255.0 U 0 0 0 eth1
192.168.10.0 * 255.255.255.0 U 0 0 0 eth0
169.254.0.0 * 255.255.0.0 U 0 0 0 eth1
127.0.0.0 * 255.0.0.0 U 0 0 0 l0


Thanks,
Thiru

There's no default gateway set on the RH machine. The line with '169.254.' probably was written to work this way, but it's probably not enough.