With NIS+ how do I find out which machine a client is bound to?

NIS+ clients do not hard bind to nis+ servers in the same
way that NIS clients bind to NIS servers. The clients have a
list of NIS+ servers within the cold-start file. When they need
to do a lookup they do a type of broadcast called a "manycast"
and talk to the first server that responds. This way they can
be sure to use the lightest loaded server for the request.