Getting NLB to work in a virtual environment is always a pain in the neck. For example, try figuring out if VMware workstation 7.0 supports Unicast or Multicast NLB. Go ahead, just try it. Tom even posted a question on the typically very useful message boards over at www.vmware.com and got no answer at all. You’d think with all the users of VMware Workstation out there one person would have used NLB with VMware Workstation.
Well, too bad for VMware – it’s just another reason why you should be using Hyper-V for your test bed. Not that it’s always been easy to get NLB in unicast mode to work on Hyper-V. In fact, if you’re using Windows Server 2008 RTM, there are some hotfixes you need to apply, and then you need to configure custom MAC addresses in the Hyper-V NIC interfaces.
If you don’t know how to do this, then check out this blog post by Gershon Levitz – he shows you step by step, complete with screenshots, how to get unicast NLB to work with TMG on Windows Server 2008 . Check out his blog post on this top at:
BTW – if you’re using Windows Server 2008 R2, you don’t have to worry about this issue, as unicast NLB support is included with Hyper-V right out of the box, with a new feature called Enable spoofing of MAC addresses. You’ll see that in the properties of the virtual NIC, and it should be enabled by default.
DEBRA LITTLEJOHN SHINDER
MVP (Enterprise Security)