When you propagate an NIS map, you copy it from one server to another--most often from the master to all NIS slave servers. Initially, ypinit propagates the maps from master to slaves, as described previously. From then on, you must transfer updated maps from master to slaves by running the ypxfr(1Mnis) command.
You can run ypxfr three different ways:
yppush runs on the master server. yppush copies, or ``pushes,'' a new version of an NIS map from the NIS master to the slave(s). After making a list of NIS servers from the ypservers map built by ypinit, yppush contacts each slave server in the list and sends it a ``transfer map'' request. When the request is acknowledged by the slave, the ypxfr program running on the slave does the actual transfer of the new map to the slave.