NAME

ypbind — create and maintain a binding to a NIS server

SYNOPSIS

ypbind

[-broadcast] [-insecure] [-ypset] [-ypsetme]

DESCRIPTION

ypbind finds the server for a particular NIS 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 <domain>.version, where <domain> is the relevant domain. The NIS system only supplies information on version 2.

If ypbind is started without the -broadcast option, ypbind steps through the list of NIS servers specified in /var/yp/binding/<domain>.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 NIS hosts map.

If ypbind is started with the -broadcast option, or if /var/yp/binding/<domain>.ypservers does not exist, ypbind broadcasts to find a process willing to serve maps for the client's domain.

Once a binding is established, 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. If a binding cannot be re-established within 60 seconds, ypbind backs off exponentially to trying only once per hour.

The options are as follows:

-broadcast

sends a broadcast requesting a NIS server to which to bind.

-insecure

do not require that the server is running on a reserved port. This may be necessary when connecting to SunOS 3.x or ULTRIX NIS servers.

-ypset

ypset(8) may be used from anywhere 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 -broadcast, -ypset, and -ypsetme options are inherently insecure and should be avoided.

SIGNALS

ypbind responds to the following signals:

HUP

causes ypbind to immediately retry any unbound domains that are currently in exponential backoff. Use this to resume immediately after a long network outage is resolved.

FILES

/var/yp/binding/<domain>.version - binding file for <domain>. /var/yp/binding/<domain>.ypservers - explicit list of servers to bind to for <domain>.

DIAGNOSTICS

Messages are sent to syslogd(8) using the LOG_DAEMON facility.

SEE ALSO

domainname(1), ypcat(1), ypmatch(1), ypwhich(1), nis(8), yppoll(8), ypset(8)

AUTHORS

This version of ypbind was originally implemented by Theo de Raadt. The ypservers support was implemented by Luke Mewburn.