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I have a 2 node failover cluster running on Windows 2008 R2.

The cluster is functioning and I can failover services between the two nodes. All was working fine last week but now nothing can connect to the cluster unless it is on the same subnet as the virtual ip for the resource.

For example:

  • My machine (different subnet) can ping node 1 (
  • My machine (different subnet) can ping node 2 (
  • My machine (different subnet) cannot ping virtual ip (
  • A server (same subnet) can ping node 1 (
  • A server (same subnet) can ping node 2 (
  • A server (same subnet) can virtual ip (

There is also nothing in the cluster validation report that suggests it could be causing this issue.

What could be causing this?

Any help would be greatly appreciated

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Are you also using Network Load Balancing? – longneck Jan 14 '13 at 14:45
No, just Microsoft Cluster services – ts404 Jan 14 '13 at 15:27
Because you can ping the dIP and not the vIP I would suspect something with the vMAC and ARP. – joeqwerty Jan 14 '13 at 23:30

see this:

Gratuitous ARP requests must be forwarded across networks so that all devices receive the updated MAC-to-IP address mappings. Contact your hardware manufacturer for information about how to change your switch or router's configuration so that gratuitous ARP requests are passed to all networks.

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  1. Check route(s) from "different subnet" to "same subnet"
  2. Check firewall between "different subnet" to "same subnet"

In case you are pinging DNS names instead of IP's:

  1. Check DNS
share|improve this answer
Routes seem fine, there is no firewall and DNS is working correctly. I cannot ping via name or ip address, the the name is resolved to the correct virtual IP. – ts404 Jan 14 '13 at 15:28
Well, it's hard to tell the reason without more detailed info. We would need some tracelog, route tables, etc.. – tomaac Jan 14 '13 at 15:46

try clearing the ARP table from the network end. Also there could be issues with Ghost NICs if the machines are Virtual machines and if there is a NIC teaming implemented

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