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I'm trying to setup Network Load Balancing for the first time on Windows 2008 R2 and have it working, but am just wondering, if I have a block of 5 public IP addresses from the ISP:

123.456.789.012 - 123.456.789.016

I have it so that NLB listens on the IP address of 123.456.789.012 (this is also the address my DNS record points to from my public domain name), do I need to have my IIS servers having public IP addresses?

Right now IIS Server 1 uses 123.456.789.013, and IIS Server 2 uses 123.456.789.014. I'm just worried that as I grow this solution, we're going to need to add up to possibly 10 IIS servers, so we'll require IP addresses for each server.

Each server will be hosting 2 websites so we could require up to 20 public IP's just for this. Our ISP limits us to 14 public IPs. Not sure if there is a better way to do this?

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Foregoing IPv6, the way to work around IP address limitations is NAT. Your firewall most certainly supports this. That means you can use private address ranges for your internet facing servers and you only need to NAT your public IP address to the VIP private address of your NLB. That way you can scale out your NLB cluster to the limit of the maximum supported nodes and still only consume one public IP address.

See for an example of such a setup.

Best regards,

Didier Van Hoye

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