Problems setting up a NIS Slave Server

When I first trying to start a NIS slave server in my network, it complained:

Can't enumerate maps from server.example.com. Please check that it is running.

Appearantly, ypinit failed to enumerate maps using yphelper. The source of the problem turned out to be the DNS configuration. server.example.com had several DNS entries. I had to specify the name that the reverse lookup of its IP returned and then ypinit worked.