We've got a weird situation happening on a backend Exchange cluster. Here is a our Current setup:
Front end in DMZ
2 backend clusters Cluster01, Cluster02 behind firewall
Cluster01 has 4 nodes Node A and B are a pair and Node C and D are a pair
The active node of Cluster01 pair C and D Intermittently loses the ability for RPC over HTTP but a fail over fixes the issue. Those same users can still use OWA. Users on Cluster01 A and B pair have no problem nor does Cluster02 with rpc over http during the same time that cluster01 pair C and D are having problems. So it's narrowed down to node pair C and D but I'm not sure where to go at this point.