A question that often comes up is which modes of NLB does UAG support. Initially, before UAG SP1 came out, support was limited to Unicast, even though the UAG User Interface allowed the user to select all 3 modes (Unicast, Multicast and or IGMP Multicast). To add to the confusion, there were some blog posts and other documents that contradicted each other.
To make this clear, we have edited the public documentation on this topic to say “From Forefront UAG SP1, Forefront UAG DirectAccess supports NLB in Unicast, Multicast, and IGMP Multicast modes.” To be clear, this means that for non DirectAccess (meaning Application Publishing scenarios), only Unicast is supported. In other words, if you are creating trunks on your UAG server, you can assign regular IPs, or VIPs configured with Unicast, but *not* VIPs configured with Multicast or IGMP Multicast. If you are configuring DirectAccess, you can assign any IP or VIP to the DA configuration, no matter which type of casting they use. If the UAG server has both Application publishing and DirectAccess, the same rule applies – Unicast only to the trunk or trunks, anything to the DA configuration.
If you run into any other source of information that contradicts the above, please notify me, so I can have it corrected.