Currently we have a working NLB cluster of web servers running Windows Server 2008 R2 and IIS 7.5 with one virtual IP address.
We have three web servers in the cluster the VIP is 141, and the web servers each have an IP address of 142, 143 and 144.
We need to add another web site bound to a seperate IP address - we need to do this because we need a seperate and completely different SSL Certificate for the new site and IIS doesn't support two certificates on the same site (ref Thread - Multiple SSL Certificates on a Web Site in IIS 7).
One option for us is to add another VIP say 151, and add new local addresses - for example - 152, 153 and 154, and then make a new site bound to new IP(s).
Please can you tell me, if this is possible and is it a supported production configuration?
Microsoft says yes and yes. http://support.microsoft.com/kb/556067
When using the NLB manager you should notice that "Cluster IP Addresses" is plural. You can add more than one there. I'm pretty sure that the single-subnet rule is still active. All of your cluster and system IPs should be in the same subnet, (only one mask and gateway are allowed, essentially).