I have setup a windows NLB on two web front ends WFE1 and WFE2. I have set WFE1 as priority 1 and when user browses the site they hit WFE1. This works fine.

To test a fail over scenario I stopped the WWW publishing service (which stops IIS) on WFE1. When the user browses the portal his request are still served by WFE1 and since IIS is down the portal returns blank page. I expected that the request will be served by WFE 2 but it seems Windows NLB is not intelligent enough to check if the services are running on WFE 1 and route to WFE 2. It only works if I stop the host on NLB cluster then the request goes to WFE 2.

How do I handle this scenario and are there any configurations on Cluster/Host that need to changed.

1 Answer 1


The NLB "heartbeat" is just broadcast TCP/IP packets over the network, so it doesn't really check for actual availability of the site or services.

If you require a more complex heartbeat you'll have to look into other load balancing solutions. I'm no expert on it but you have F5, Cisco and other hardware load balancers that will allow you to do this.

  • Thanks steven. My client has also accepted this and that what you get from Windows NLB. Commented Jul 31, 2013 at 22:05

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