Windows 2003 NLB - Virtual IP Problem

[venusridhar]

Hi All,

We have a requirement of setting up web farm for our application. I tried setting up with the following setup.

We have setted up two Windows 2003 Enterprise edition servers both having complete application with IIS configured.

I have followed the instructions for setting up the Network Load Balancing utility (NLB) comes with Win2k3 and configured two clusters.

I have configured correctly with a virtual ip being used by two nodes and both the hosts in the cluster and converged correctly.

But the issue is i could able to browse the url of the dedicated ips of the machines thru lan, but thru the virtual ip (or load balanced ip) i cannot able to view the application.

Since the virtual ip if i can access then only the application will be load balanced, i am thinking of what will be issue.

Any body could throw light on this.

thanks and regards,

Venugopal

[cluberti]

Is your cluster operation mode unicast or multicast, and is the IP address you chose for the virtual IP address configured as an IP on your network, with the correct subnet mask? If these servers all have only one network adapter, you MUST be using multicast (and thus, your network must be able to handle multicast traffic).

[venusridhar]

Hi,

Thanks for your reply.

The configuration settings is like this.

1. 2 Servers on Win2k3 Server Edition

2. Single Network Adapter

3. NLB Configured on Multicast with IGMP Support

4. Both Hosts Converged

The IP address are

Host 1

Virtual IP : 10.0.1.101

Subnet Mask : 255.255.252.0

IP Address : 10.0.1.155

Gateway : 10.0.1.1

Host 2

Virtual IP : 10.0.1.101

Subnet Mask : 255.255.252.0

IP Address : 10.0.1.151

Gateway : 10.0.1.1

And I can able to access the application within the hosts. But if i try to access the application outside the host in the lan, i am getting HTTP Error.

The Same application if i Try to access with the Machine's Dedicated IP address it works.

And the Virtual IP Address ping successfully on all the machines.

Eg:

http://10.0.1.101/testing.html -> Within Host Works -> Other than Host : HTTP Error

http://10.0.1.151/testing.html -> Works (dedicated IP)

I will be happy if i could get any thoughts on this.

Regards,

Venugopal.P

[cluberti]

You will probably need to get a network trace from a client machine with something like netmon or ethereal to see exactly what is going on. It could be any number of things, but a network trace of the failure (and possibly a network trace of the success from the server) would shed some more light on what exactly is happening to the packets during the transfer.

[venusridhar]

Hi,

How about the Settings we have made. Is that fine. I am just wondering if there any problems with settings. And also thinking why after convergence it is not able to load balance.

Regards,

Venu.

[cluberti]

At this point, you'd only be guessing - it looks like an OK setup, however, so the only way to be sure is to actually watch the packets using a network trace to see exactly what happens.

That setup does look like it was done correctly, though.

[venusridhar]

Hi,

Thanks for your Reply. Lemme Check out the Networking issues. I found in some article that NLB Won't work if the switch used by the Hosts is Layer3. Will it be an issue.

Regards,

Venu.

[cluberti]

Depending on the switch and whether it recognizes the virtual IP or not, that'd be a possibility.

[venusridhar]

Hi,

I need to discuss one more issue regarding this. I can able to access the virtual IP when only one machine is converged. The HTTP error comes if say two machine are converged.

What might be reason.

Regards,

venu.

[cluberti]

Actually, that does sound like a network hardware issue at that point.

[venusridhar]

Thanks for your Reply.