UAG NLB with public IP VIP, private for NIC IP address? RRS feed

  • Question

  • So if you are using UAG Network Load Balanacing (NLB) where your Virtual IP (VIP) is going to be a public IP address, what addresses would the various external NIC interfaces for the UAG array use. I'm assuming Unicast method is used.

    So if I have a real public IP for my VIP, can I use private IPs for my external addresses or to the NICs also have to have public IP addresses?

    For example if my VIP was (social.technet.microsoft.com) can I use 192.168.x.x for my addresses on the external NIC of each UAG in the array even though nothing else is going to know about or use those addresses? Specifically any network devices on the internet side of UAG are only going to know the VIP and have no explicit knowledge of the 192.168.x.x addresses.

    I know the external NIC addresses all need to be in the same subnet, but I wasn't sure about their relation to the VIP or other devices that might talk to the VIP. I did some searching but didn't find anything on this specific topic.
    Wednesday, March 17, 2010 3:57 PM


  • Nope, the dedicated IPs (DIPs) and virtual IPs (VIPs) need to exist in the same subnet. So, you will need three public IP address for the bare minimum with NLB setup with one VIP.

    If you plan to use DA, you will need two public IPs for VIPs and two public IPs for DIPs (one for each UAG).


    Jason Jones | Forefront MVP | Silversands Ltd
    • Marked as answer by Erez Benari Thursday, March 18, 2010 9:52 PM
    Wednesday, March 17, 2010 4:04 PM