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

# 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.

June 14, 2014 | NetBSD 9.5