communication problem between two subnets

UNIX for Advanced & Expert Users
1

We have two Sun Sparc systems running on the xxx.xxx.1.xxx network and can be access fine by machines on that subnet. We are able the ping one of the machines from the xxx.xxx.2.xxx network, but we are not able to ping or communicate with the other machine on the (1) subnet from the (2) subnet.

I'm not a unix junkie but our unix people are feeling this is a switch problem. We networking folk feel otherwise since we are able to communicate with one machine through the same switch.

The machines are "configured" the same. The net mask on both machines are the same.

Any ideas? Thanks for any input.
JP

2

sounds like a routeing problem.

do both machines have the same /etc/defaultrouter settings? If not are the routers set up properly?

3

Thanks for the quick response. Could you tell me how to check these?

As I mentioned, I'm not very familiar with Unix.

Thanks again
JP

4

cat /etc/defaultrouter do that on both machines.

5

"netstat -r" on both systems will show the route table on each machine.

Make sure both machines can ping their default routers and make sure the default route on each machine is pointing to their routers' IP address. If the default route is set correctly and they can ping their router, then it's probably a routing issue at the router.

:cool:

6

Make sure your netmasks are set correctly for each subnet. Incorrect netmasks can cause strange problems like these.

7

OK, there do seem to be some differences. We will be having our people make the changes ASAP. We'll let you all know. Thanks so much for the assistance.
JP

8

Thanks to all again for the input and assistance. We found the netmask to be different on the machine that was not working. Once changed all is cool and working just fine.

JP

9

It is one of two things -

1 - A routing problem

Check to make sure the router - or the Route Switch module in the switch is configured correctly (Netmask, etc.)

2 - Default gateway is not set on one of the Unix Machines

Check to make sure that the default route (default Gateway is set). I would bet money that this is the problem.

Hope this helps.

KO