Hello,

Recently i am trying to set up my Linux box as a router. It has two NICs which are working fine(to ping itself alive).

The first "eth0" has a static address of 202.x.180.72 which connects to my Switch then Intel router. The second "eth1" has a static address of 192.168.10.1 which is connected to a hub and consequently my internal network.

From the linux box router, I can ping the outside network througt out eth0, so i think the default gateway 202.x.180.65 setting is correct. However, I cannot get to the internet from the 192.168.10.0 net nor ping 202.x.180.0 (destination net unreachable), furthermore, i found that eth0 & eth1 can't even ping each other inside the linux box. I thought I had set up ip packet forwarding correctly (i did already "echo 1 > /proc/sys/net/ipv4/ip_forward"), but apparently not.

I think i am getting something wrong or some missing in the "route add" syntax.

Any help or suggestion would be appreciated!!


----------------------------------------
INTERNET
----------------------------------------
|
ROUTER 202.x.180.65
|
|
SWITCH
|
|
---------------------------------------
eth0:202.x.180.72
|
Linux Router
eth1:192.168.10.1
--------------------------------------
|
|
192.168.10.0 Network

Some more info about the kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
202. x.180.72 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
255.255.255.255 0.0.0.0 255.255.255.255 UH 0 0 0 eth1
202. x.180.64 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
192.168.10.1 0.0.0.0 255.255.255.255 UH 0 0 0 eth1
192.168.10.0 0.0.0.0 255.255.255.255 UH 0 0 0 eth1
202. x.180.64 202. x.180.65 255.255.255.192 UG 0 0 0 eth0
202. x.180.64 0.0.0.0 255.255.255.192 U 0 0 0 eth0
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 202. x.160.65 0.0.0.0 UG 0 0 0 et0

Have you set the default gateway on the machines in the 192.168.10.0 network to 192.168.10.1?

The linux router seems to be configured fine

Actually, NO..... would you show me how??

I just try the following:

route add -net 192.168.10.0 netmask 255.255.255.0 gw 192.168.10.1 dev eth1


but eth0:202.x.180.72 still cannot ping eth1???!!


any help?

route add default gateway 192.168.10.1

Everything that doesn't have a specific destination that the local machine knows about will then get sent on to 192.168.10.1. The linux router in turn has a default gateway to reach the internet so the traffic will get sent onwards toward the internet.

no luck !!?

When i try to "ping 192.168.10.1 -I eth0", then the screen comes up>>
PING 192.168.10.1 (192.168.10.1) from 202.x.160.72 eth0: 56(84) bytes of data.
and stop response until i press <CTRL+C>.

current routing table:
202. x.180.72 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
255.255.255.255 0.0.0.0 255.255.255.255 UH 0 0 0 eth1
202. x.180.64 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
192.168.10.1 0.0.0.0 255.255.255.255 UH 0 0 0 eth1
192.168.10.0 0.0.0.0 255.255.255.255 UH 0 0 0 eth1
202. x.180.64 202. x.180.65 255.255.255.192 UG 0 0 0 eth0
202. x.180.64 0.0.0.0 255.255.255.192 U 0 0 0 eth0
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0 0 eth1
0.0.0.0 202. x.180.65 0.0.0.0 UG 0 0 0 eth0

Don't add the default gateway on the linux router. You already have the default gateway going to the external interface. Set that default gateway on each of the client machines on the 192.168.10.0 network.

Something like this:

Linux router
eth0 IP: 202.x.180.72
eth1 IP: 192.168.10.1
default gateway: 202.x.180.65

Client machine
eth0 IP: 192.168.10.3
default gateway: 192.168.10.1

Thanks for the info, i'll give it a trial when i back to the office.

Regards,
Trunks