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

     ypserv -- YP server daemon

     ypserv [-1dx] [-a aclfile]

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

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

     YP hasn't been known for high security through the years.  In recent
     years security has improved by restricting access to the server.  In
     SunOS 4.1 has a new file occurred named /var/yp/securenet.  It contains
     networks the server can assume is secure.  For information about the file
     format, see securenet(5).

     Before the author of this server had seen securenet(5) another format,
     ypserv.acl(5), was implemented.  This file format makes it possible to
     allow and deny hosts and networks access to the server.  This file can
     have any name since it's given by the argument to -a (use full path).

     If a host isn't secure all queries to the server will result in a
     YP_NODOM result.

     If the file /var/yp/ypserv.log exists then messages will be written to
     the file.

     If a directory named the same as the system domainname exists in /var/yp
     (i.e., the domainname is ``foo'' and the directory /var/yp/foo exists),
     then ypserv will be automatically started at boot time.

     On receipt of a hangup signal, SIGHUP, ypserv will reopen the log file
     and reread its configuration, including both the db(3) map files and the
     ypserv.acl(5) or securenet(5) configuration file.  The process ID can be
     found in the file /var/run/ypserv.pid.

     The options are as follows:

     -1      Allow ypserv to answer old YP version 1 requests.

     -a aclfile
             Don't use /var/yp/securenet.  Use another file with a different
             file format.  For further information see ypserv.acl(5).

     -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 successful.  Alternately, if these maps were
             built on the YP master using makedbm -b then DNS queries will be
             done without needing to specify -d.

     -x      Terminate the server after processing aclfile or


     securenet(5), ypserv.acl(5), Makefile.yp(8), yp(8), ypbind(8)

     Mats O Jansson <moj@stacken.kth.se>

BSD                              May 30, 2017                              BSD