External NIC cards not pinging with each other in RHEL 5.1

Linux and Unix-Like Red Hat
1

We have a setup of two nodes which has two NIC cards in each. One is built in and another is D-Link (external NIC card). We are unable to ping to the external NIC cards in both. Eg: Node A has two IPs 192.168.1.10 (eth0) and 192.168.2.10 (eth1) and Node B has two IPs 192.168.1.20 (eth0) and 192.168.2.20 (eth1). These setup has two switches, where 192.168.1.10 and 192.168.1.20 is connected to Switch A, 192.168.2.10 and 192.168.2.20 is connected to Switch B.

The problem here is from 192.168.1.10 is able to ping 192.168.1.20 but not to 192.168.2.20 same with the Node B 192.168.1.20 is able to ping 192.168.1.10 but not 192.168.2.10. when all are placed in same network then all IPs are pinging with each other.

All Linux gurus please help me .. pls treat this request as high prioprity!!

2

you must define a route, telling your system to ping the net 192.168.2.0 not over the default gateway, 192.168.1.1 or 254, or whatever is defined, instead over interface 192.168.2.10

before you set the route, pls post the output of netstat -rn

route add -net 192.168.2.0/24 ethx

where ethx ist the interface with the 192.168.2.x ip

tells your system to ping every ip in the range 192.168.2.1 - 192.168.2.254 over the interface with the ip 192.168.2.x

Edit: make sure you have a console connection, or another possibility to reach the server without network when you change routes

and the route assumes a netmask of 255.255.255.0
if theres a routing defined between the two networks in your company, then maybe it's another problem
ask your network team if this networks are routet

3

Hi Thanks for the quick reply.. I'm also the part of the same team.

I have tried adding the route to the 192.168.2.0 network from both the machines.. I have tried all the possible solutions, do you think any service is stopping the external card to ping each other?

4

iptables may block icmp requests

try to reset the routing table on both sides

can you ping the default gateway from the 192.168.2.0 net, if there is one from one side?

switch/router may block different ip adresses too, check acls