Ping issue with my one of my 2 IIS Clusters

Hello,

I'm encountering a really strange problem with one of my web server Cluster.

He can't ping any of the internal network hosts : (cannot reach host).Besides, only the other web cluster can ping him.

It's not a firewall issue, cause he exactly has the same config than the first web server cluster, and this last one can ping everyone, and can be pinged by everyone.

So server A (192.168.1.4) responds to ping, can ping everyone, including server B (192.168.1.5).

Server B can't ping anyone (host unreachable), except Server A.

(the web cluster responds to the IP : 192.168.1.6)

Thanks for the responses .