Windows Network Load Balancing Not Working

[helphelphelp]

Hi,

 

I have an issue with Windows NLB and I'm not sure if it should be behaving like it is right now. Basically, I installed Windows Server 2008 R2 on two VMs using ESXi 4. Installed IIS and NLB on both servers. Set one server's priority to 1 (Server A)) and the other's to 2 (Server B)). All ports allowed and affinity set to single. Communication set to multicast. I tested access using another VM on the same network.

 

[Affinity=Single]

With both servers online, I telnet to the cluster IP and hostname on port 80. No problems.

Then I brought Server A offline. Server B remains online. Telnet fails on both cluster IP and hostname.

Next, I brought Server A online and Server B offline. Telnet sometimes work and sometimes fail on both cluster IP and hostname. Seems unstable.

 

[Affinity=None]

With both servers online, I telnet to the cluster IP a nd hostname on port 80. No problems.

With Server A offline and Server B online, telnet sometimes work and sometimes fail on both cluster IP and hostname. Unstable.

With Server A online and Server B offline, telnet sometimes work and sometimes fail on both cluster IP and hostname. Unstable.

 

The above observations are not normal, are they? Can someone kindly explain what is happening behind the scenes and what I can do to solve the problem?

 

Greatly appreciate all help that I can get!

 

Regards,

Alwyn