Hello!

I am using a linux machine as a router / firewall to my home network. The server is running Fedora 15, and is connected to the outside world via a ppp interface (on em1). Internally, I have a subnet set up on 192.168.2, with the server NIC (p4p1) set to 192.168.2.1. Each machine can ping 192.168.2.1 (and can communicate with the outside world), and the server can ping each machine. However, the machines are not able to ping each other.

This is the routing table:

192.168.2.0 * 255.255.255.0 UG 0 0 0 p4p1
192.168.1.0 * 255.255.255.0 U 0 0 0 em1
link-local * 255.255.0.0 U 1002 0 0 em1
link-local * 255.255.0.0 U 1003 0 0 p4p1
default my-gw 0 0.0.0.0 UG 0 0 0 ppp0

This setup has worked for me many times before, so I am baffled as to why I can't get it working this time.

Any network geniuses with some ideas?

Do you have any pertinent switch configuration or is it a flat switch?

1 members found this post helpful.

In theory, should be flat. I have a dumb hub attached to p4p1, and a second device (Buffalo Airstation) in non-routing mode acting as my wireless hub.

... but your question got me thinking outside of the box (literally). I have always assumed that my Buffalo was acting as a flat switch. I'd better test that assumption. :-)

Thanks for the tip!

So the machines are 192.168.2.xx and 192.168.2.yy and they can not ping each other?

Server is 192.168.2.1 and can ping 192.168.2.xx?
Server is 192.168.2.1 and can ping 192.168.2.yy?
192.168.2.xx can ping server at 192.168.2.1?
192.168.2.yy can ping server at 192.168.2.1?

That is simply not possible. Since they are on the same subnet routing is not an issue.

Are 192.168.2.xx and 192.168.2.yy static addresses?
If not, assign them static addresses.
Run a network cable straight between the 192.168.2.xx and 192.168.2.yy
Make sure the NICs are modern and auto-sensing. If not, create a cross connect.
See if you can ping.

jlinkels

Ok, it was indeed some weird problem with the wireless hub. The settings were correct, but it was in an incorrect state. A reboot fixed the problem.

Thanks to szboardstretcher and jlinkels for the help. I was literally thinking in the (linux) box and didn't see the problem.