How to Test Packet Filter and NIC Compatibility.



This Knowledgebase article provides information about how to test packet filter and NIC compatibility.


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Due to the number of NIC’s in the market place, it may be necessary from time to time to test compatibility with Neverfail Packet Filter software.


Compatibility Test

When using Neverfail Heartbeat, the Secondary server is configured with the same principal (public) IP address and system name as the Primary server. During normal operation, network traffic directed to this principal (public) IP address is blocked on one of the servers, thus avoiding name and IP address conflict errors. The component used to block the traffic to the principal (public) IP address is the Neverfail Packet Filter.

The Packet Filter can be controlled using: \R2\bin\NfPktFltr.exe

After Neverfail Heartbeat has been installed and you have configured the principal (public) IP address using the Configure Server wizard, you can test the Packet Filter in the following way:

Note: Disable the NIC with the principal (public) address on the Secondary so it does not interfere with the test on the Primary.

  1. On the Primary server, allow the IP traffic to pass through using the following from the command prompt: NfPktFltr.exe enable
  2. On a client system: Ping the principal (public) IP address - this should succeed.
  3. On the Primary, block the IP traffic using the following from the command prompt: NfPktFltr.exe disable
  4. On the client system: Ping the principal (public) IP address - This should fail. (If this succeeds, the NIC is not currently supported.)
  5. Disable the NIC with the principal (public) IP address on the Primary and enable it on the Secondary server, and repeat the test on the Secondary server.

Using the arp -a command before and after switching from the Primary to Secondary servers will show different MAC address registered against the IP address.

Note: If a test fails, try updating the driver for the network card. If the driver is already the latest version, try the previous version.


Applies To

All Versions


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