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Loss of communication in a Windows 2008 Server cluster with Network Load Balancing (NLB) in PCOP 5.x versions

Information applies to:

Endpoint Protection

Operating systems
Windows Server 2008


In PCOP 5.x versions, once the protection is installed, the different cluster nodes are not able to see and communicate with other members of the cluster.


The issue is due to the fact that Microsoft Network Load Balancer (NLB.SYS) is incompatible with NDIS 5.0 and NDIS 5.1 Intermediate Filter drivers.

For further information, refer to NDIS 5.x Intermediate Filter drivers are incompatible with Network Load Balancing (NLB.SYS).


If you are running PCOP 5.x version, contact your Panda Support office and request the upgrade to latest version available.

On the other hand, if you don't want to upgrade your product, you can also follow the instructions below, once you have installed the protection:

  1. Open the network properties. To do that, go to Start -> Control Panel –> Network and Internet –> Network and sharing Center, select the Connection and then Properties.
  2. Deactivate PANDA NDIS IM Filter.
  3. Repeat this process in every node of the cluster.
  4. Check that the issue is solved.

Help nº- 20130425 50048 EN

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