I was asked to visit a customer who was having problems federating a primary node (Meeting server) with the SSC. They had some other problems as well which meant that I thought it was best to uninstall, clean up and reinstall.
After the two Meeting servers were reinstalled I hit the same problem when trying to federate the primary node. I looked in the addnode.log and noticed an error with an exception, unfortunately I didn’t take a note of the error but the crux of it was that during the addnode process the IP address the DM was resolving for the PN was incorrect.
Looking at the Windows 2008 server I noticed that it had two NICs, a primary and a management LAN. I added host file entries for the SSC and the two Meeting servers to all three servers after which federation worked fine.
I do not know why WAS picked the management IP, there is probably an algorithm it uses to decide but it is wise to be mindful of this if installing on a server with multiple IPs.