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YPSERV(8)		  BSD System Manager's Manual		     YPSERV(8)

     ypserv -- NIS server daemon

     ypserv [-dfl] [-p port]

     ypserv is a fundamental part of the network information system called
     NIS.  This	server provides	information from NIS maps to the NIS clients
     on	the network.

     A NIS map is stored on the	server as a db(3) database.  A number of NIS
     maps is grouped together in a domain.  ypserv determines the domains it
     serves by looking for a directory with the	domain name in /var/yp.

     In	an effort to improve the security of NIS (which	has, historically, not
     been very good), this ypserv has support for libwrap-based	access con-
     trol.  See	hosts_access(5)	for more information.  The daemon used for ac-
     cess control is the name which ypserv was invoked as (typically
     "ypserv").	 If a host is not allowed to query this	NIS server, ypserv
     will return the NIS result	code YP_NODOM.	To avoid problems with DNS
     lookups causing ypserv to hang, ypserv disables DNS lookups for its
     client hosts_access(5) lists.  The	result is that ypserv can only use ad-
     dress based patterns.  This also means that wildcard patterns such	as LO-
     CAL or KNOWN will not work.

     The process pid of	the ypserv process can be found	in the file

     The options are as	follows:

     -d	     Use internet Domain Name System.  If a query to map hosts.byname
	     or	hosts.byaddr fails, make a DNS query and return	the result if

     -f	     Run in the	foreground.

     -l	     Enable logging of all requests.

     -p	port
	     Bind to the specified port	instead	of dynamically allocating one.

     All messages are sent to the system log with the facility LOG_DAEMON.
     Error messages have the priority LOG_ERR.	Refused	requests are logged
     with the priority LOG_WARNING.  All other messages	are logged with	the
     priority LOG_INFO.


     syslog(3),	hosts_access(5), nis(8), syslogd(8), ypbind(8),	ypinit(8)

     This implementation of ypserv was originally written by Mats O Jansson
     <>.  The	access control code was	later re-written from
     scratch by
     Jason R. Thorpe <>.

BSD				 May 20, 2006				   BSD


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