Hello-

CLIENT A - 10.10.10.2
|
ROUTER - eth0 - 10.10.10.1
ROUTER - eth1 - 10.10.20.1
|
|
SERVER eth0 - 10.10.20.2
SERVER eth1 - 10.10.30.1
|
|
CLIENT B - 10.10.30.2

CLIENT A/B - Windows XP SP3 with FW off
SERVER - Ubuntu 9.10

Everything is working fine and CLIENT A can talk to CLIENT B and vice versa, with only one problem - CLIENT A cannot ping 10.10.30.1.

I checked routing several times, there is no NAT and firewall is disabled on the SERVER.

CLIENT B can ping and access any device in the diagram.
CLIENT A can ping and access any device in the diagram too, however cannot ping eth1 of SERVER (10.10.30.1).
ROUTER can ping any device in the diagram except eth1 of SERVER (10.10.30.1).

If I launch 'ping 10.10.30.1' from CLIENT A and run tcpdump on SERVER eth0 I see no hits at all.
If I launch 'ping 10.10.30.1' from CLIENT A and run tcpdump on SERVER eth1 I see ICMP requests coming from CLIENT A but no replies.

It doesn't look like a routing problem because clients A and B can communicate with each other.
Also, we have around 20 similar installations but this is the first time CLIENT A cannot ping internal interface of SERVER.

Any hints would be greatly appreciated!

Just a thought...is pinging disabled? It is possible to disable the pinged machine from responding to a ping...this is a security measure...

This this:

and see if a ping reply happens now...

All of the magic happens in the networking script

where ping response is enabled/disabled

Luck!

Thor

Tried that. It's enabled, but thanks anyway!