Hi,

I have rather strange and unresovable error on my 3 Linux servers, all are HP servers, HP DL140, HP ML350 and HP DL360. All running Ubuntu 6.06.

There is a problem that the extra static route it need to add doesnt work, well not all the time.

Basically there are two networks 192.168.197.0 and 192.168.198.0 with a router at 192.168.197.1/192.168.198.1 that allows routing between the two networks. on the 192.168.197.0 network there also is a firewall on 192.168.197.254 this is the default gateway for this network and what the Linux servers use as a default gateway to access the internet.

As the default gateway is .254 i added a static route on the server to point to the .1 router to access the 192.168.198.0 my routing table looks like this.

root@xenon:~# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.197.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.198.0 192.168.197.1 255.255.255.0 UG 0 0 0 eth0
0.0.0.0 192.168.197.254 0.0.0.0 UG 0 0 0 eth0

Looks okay to me, but it doesnt work, well not all the time. from the 192.168.198.0 network i started to ping the Linux server (whose routing table is shown above), and it didnt work, then after half an hour of pinging, i suddenly started to get a response from the server.

I've then tried pinging it this morning and it doesnt work again, nothing has changed over night, but its stopped working again.

This seems to be a bug, or have i done something wrong? This seems to me to be a very simple configuration for a routing table. Is there anyway to fix this?

Thanks

Tristan

I think you should check this.

Hi,

Can't see what you mean.

the 192.168.197.1 router (gateway) to access the 192.168.198.0 network.

Is there something wrong with the syntax?

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.197.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.198.0 192.168.197.1 255.255.255.0 UG 0 0 0 eth0
0.0.0.0 192.168.197.254 0.0.0.0 UG 0 0 0 eth0

This is the command I entered to create the route:

# route add -net 192.168.198.0 netmask 255.255.255.0 gw 192.168.197.1

Basically use the default gateway 192.168.197.254 for all internet routes, but use the 192.168.197.1 gateway for accessing the 192.168.198.0 network.

If the server is on the 192.168.197.0 network surely this is correct?

Thanks

Okay i've given up with the static routes idea, theres obvously a bug with that.

I've pointed the server at the default gateway 192.168.197.1.

# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.197.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
0.0.0.0 192.168.197.1 0.0.0.0 UG 0 0 0 eth0

Looks fine to me, all other machines on the network (except those running Ubuntu 6.06) can access the internet, this one can't.

Basically anything off the local network is not accessable. This is a brand new build of Ubuntu 6.06 and all other Ubuntu servers are experiencing this problem, the windows boxes however can access off network fine.

What makes it more strange is the problem is intermittent, it will work for about 30 seconds then will suddenly stop being able to access off network, then all of a sudden it will start to work again and so on.

Is there anywhere (log files) that i can check to see what is going on?

Thanks

Right packet traces are not showing the traffic even getting on the wire so it is something on the server that is stopping it from leaving the server. Anybody got any ideas what might be causing it to think traffic off the local subnet 192.168.197.0 isnt?

Thanks

Okay the plot thickens.

I setup our switch with a spanning port so i could look at etherreal captures of traffic from the Linux box to the router.

And guess what traffic is leaving the box and going to the router (Layer 3 switch) and it is ignoring it.

Has anyone known come across and issue where a Cisco router (switch) doesnt bother routing traffic from a linux box, or if it does routes it intermittently?

Thanks.