YPBIND(8)               OpenBSD System Manager's Manual              YPBIND(8)

NAME
     ypbind - create and maintain a binding to a YP server

SYNOPSIS
     ypbind [-insecure] [-ypset] [-ypsetme]

DESCRIPTION
     ypbind finds the server for a particular YP domain and stores information
     about it in a ``binding file''.  This binding information includes the IP
     address of the server associated with that particular domain and which
     port the server is using.  This information is stored in the directory
     /var/yp/binding in a file named with the convention DOMAINNAME.version.
     (The YP system only supplies information on version 2.)

     When ypbind starts the primary domain (or gets the first request for a
     new domain), it checks if a file for the domain in question exists in the
     directory /etc/yp/ (i.e., /etc/yp/DOMAINNAME).  If such a file exists, it
     will list the hosts which ypbind should restrict its server search to.
     Otherwise, ypbind assumes it will need to use broadcasts to find a valid
     server.  Using either of these techniques, ypbind will search for a serv-
     er willing to serve maps for the client's domain.  Once a binding is es-
     tablished, ypbind maintains this binding by periodically communicating
     with the server to which it is bound.  If the binding is somehow lost,
     e.g by server reboot, ypbind marks the domain as unbound and attempts to
     re-establish the binding.  When the binding is once again successful,
     ypbind marks the domain as bound and resumes its periodic check.

     The options are as follows:

     -insecure
             Permit binding to a ypserv(8) on a non-reserved port.  This is
             needed if receiving maps from SunOS 3.x or Ultrix.

     -ypset  ypset(8) may be used to change the server to which a domain is
             bound.

     -ypsetme
             ypset(8) may be used only from this machine to change the server
             to which a domain is bound.

     The -ypset and -ypsetme options are dangerous and should be avoided.  For
     greatest security, the use of a server list in /etc/yp/DOMAINNAME is rec-
     ommended.  The file should contain a list of valid YP server hostnames,
     with one hostname per line.  The comment character is #.

     If the directory /var/yp/binding exists, YP is started automatically at
     boot time by /etc/rc.

FILES
     /var/yp/binding/DOMAINNAME.version - binding file for domainname
     /etc/yp/DOMAINNAME - server list for this particular domain

SEE ALSO
     domainname(1), ypcat(1), ypmatch(1), ypwhich(1), yp(8), yppoll(8),
     ypserv(8), ypset(8)

     Once ypbind is running, the following pages should be reviewed in order
     to see how to enable YP support for each of the following maps:
     ethers(5), group(5), hosts(5), networks(5), passwd(5), resolv.conf(5)

AUTHORS
     Theo de Raadt

OpenBSD 4.7                      March 5, 2009                               1
