Can't access Windows 2008 NLB cluster from internet

Question

I have two dedicated servers with Limestone Networks, each with two network cards. One of them is connected to the Internet and gives me access to 5 public IPs per server. The second card is connected to their private network (they call it "Private Tunnel") which allows me to connect to the servers without wasting my bandwidth.

I could successfully create a Network Load Balancing cluster using the NLB Manager in Windows 2008 Web Edition, the nodes are converging as expected and I can ping the virtual IPs from any of the nodes. However, I can't access the cluster from the outside world.

This is how it is set up:

• Even though I have access to 5 public IPs per server, only one of them is set in the public facing network card, the secondary card holds a private network IP
• When I created the cluster, I used the private IPs to establish the connection between the nodes, but gave one of my public IPs to the work as the Virtual IP
• The network connection that connects to the private tunnel is set as "Local only" in windows network settings (it has only the Ip and Subnet mask set)

Since the nodes are converging perfectly, I can only assume the problem is outside the servers, probably on the Firewall or in the network settings for the Limestone network. I'm going to contact their support but I don't know what to as them to do, any ideas?

Answer 1

Check to make sure that you have a web site listening on the virtual ip address, not just the public facing ip address.

You need a site that is bound to your virtual ip address, and either has no host header value, or the proper host header value for the dns host name you are using to get to the site.

That's the first obvious things to check, I can't imagine much else at this point if you say the nodes are converging as expected.

Answer 2

Perhaps the problem here is the unicast / multicast arp cache gateway issue: blogs.technet.com/networking/archive/2009/01/15/unable-to-connect-to-windows-server-2008-nlb-virtual-ip-address-from-hosts-in-different-subnets-when-nlb-is-in-multicast-mode.aspx