Windows 2003 NLB not supporting primary TCP/IP address rules

[Shan McArthur]

Hello,

I have a Windows 2003 Server configured with NLB using a single NIC and
multicasting. The server has a dedicated IP address, which is configured as
the first IP address, and a cluster address that is configured as a second
IP address. NLB is configured properly for the dedicated IP address and the
clustered IP address.

The problem I am experiencing is that if I ping the other cluster member by
it's dedicated IP address, I get nothing back. Further investigation shows
that the server will send an ARP request for the IP address of the other
server, but in the ARP request, it uses the shared cluster IP address for
the Sender's protocol address. When this ARP request is received by the
second cluster member, it does not respond, because it sees the cluster IP
address as it's own. The end result is that network communication between
the two machines is halted.

I have confirmed the order of the IP addresses in the registry and in the
network properties box. However, if I do an ipconfig, the cluster address
is listed first.

How can I influence the order of the IP addresses so that the dedicated IP
address is listed first?

Thanks,
Shan McArthur

 

[Sandeep Rikhi]

try adding a registry key that will allow interhost communication. The key
name is

UnicastInterHostCommSupport = 1


You can either add the key manually or call the WMI method..


MicrosoftNLB_ClusterSetting:AccessNLBRegParam

Get = False

Name = UnicastInterHostCommSupport

Value = 1


After you run the method you will need to call LoadAllSettings or run "wlbs
relod"