.\"	$NetBSD: ypbind.8,v 1.5 1996/10/02 05:55:05 thorpej Exp $
.\"
.\" Copyright (c) 1996 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Jason R. Thorpe.
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.Dd October 25, 1994
.Dt YPBIND 8
.Os
.Sh NAME
.Nm ypbind
.Nd create and maintain a binding to a YP server
.Sh SYNOPSIS
.Nm ypbind
.Op Fl ypset
.Nm ypbind
.Op Fl ypsetme
.Nm ypbind
.Op Fl broadcast
.Sh DESCRIPTION
.Nm
finds the server for a particular YP domain and stores information about it
in a
.Pa 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
.Pa /var/yp/binding
in a file named with the convention
.Pa domainname.version.
(The YP system only supplies information on version 2.)
.Pp
If
.Nm
is started without the
.Fl broadcast
option,
.Nm
steps through the list of YP servers specified in
.Pa /var/yp/binding/domainname.ypservers
and contacts each in turn attempting to bind to that server. 
It is strongly recommended that these hosts are in the local
hosts file, and that hosts are looked up in local files before
the YP hosts map.
.Pp
If
.Nm
is started with the
.Fl broadcast
option, or if
.Pa /var/yp/binding/domainname.ypservers
does not exist,
.Nm
broadcasts to find a process willing to serve maps for the
client's domain.
.Pp
Once a binding is established,
.Nm
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,
.Nm
marks the domain as unbound and attempts to re-establish the binding.
When the binding is once again successful,
.Nm
marks the domain as bound and resumes its periodic check.
.Pp
The options are as follows:
.Bl -tag -width "-broadcast"
.It Fl ypset
.Xr ypset 8
may be used to change the server to which a domain is bound.
.It Fl ypsetme
.Xr ypset 8
may be used only from this machine to change the server
to which a domain is bound.
.It Fl broadcast
sends a broadcast requesting a YP server to which to bind.
.El
.Pp
The
.Fl ypset ,
.Fl ypsetme ,
and
.Fl broadcast
options are inherently insecure and should be avoided.
.Sh FILES
.Pa /var/yp/binding/domainname.version
- binding file for domainname
.Pa /var/yp/binding/domainname.ypservers
- explicit servers to bind to.
.Sh SEE ALSO
.Xr domainname 1 ,
.Xr ypcat 1 ,
.Xr ypmatch 1 ,
.Xr yppoll 8 ,
.Xr ypset 8 ,
.Xr ypwhich 1 ,
.Xr yp 8
.Sh AUTHOR
This version of
.Nm ypbind
was originally implemented by Theo de Raadt.  The ypservers support was
implemented by Luke Mewburn.