Cannot add second host to a Network Load Balance cluster

Question

I am using Network Load Balancing on Windows server 2008. (Servers have two NIC's and the cluster is configured to run in unicast mode)

I can configure the cluster on either of the hosts and add the host on which I create the cluster. However, as soon as I try to add the other node (using NLB manager), I get the following:

1. When I try to connect to the second host, an "Access denied" message appears.
2. The logon dialog requests that I enter the username/password for an account on the host with Administrator priviledges.
3. When I give valid administrator credentials, I get the message: "The RPC server is unavailable on the specified computer".

Solution

Turns out that the problem is simply UAC (User Account Control). The problem is not experienced if you:

1. Use the Administrator account
2. Turn off UAC and use an account in the Administrator group.

(I'm surprised that this is not well known, but I would guess that the Administrator account is used to configure NLB, so the situation rarely occurs)