(PHP 4, PHP 5 <= 5.0.5)
yp_master — Returns the machine name of the master NIS server for a map
$domain
   , string $map
   )
   Returns the machine name of the master NIS server for a
   map.
  
domainThe NIS domain name.
mapThe NIS map.
Example #1 Example for the NIS master
<?php
$number = yp_master($domain, $mapname);
echo "Master for this map is: " . $master;
?>