finds the server for NIS domains and maintains the NIS binding information. The client (normaly the NIS routines in the standard C library) could get the information over RPC from
ypbind
or read the binding files. The binding files resides in the directory
/var/yp/binding
and are conventionally named
[domainname].[version]. The supported versions are 1 and 2. There could be several such files since it is possible for an NIS client to be bound to more than one domain.
After a binding has been established,
ypbind
will send YPPROC_DOMAIN requests to the current NIS server at 20 seconds intervals. If it doesn't get an response or the NIS server reports that he doesn't have this domain any longer,
ypbind
will search for a new NIS server. All 15 minutes
ypbind
will check to see if the current NIS server is the fastest. If it find a server which answers faster, it will switch to this server. You could tell
ypbind
to use network broadcasts to find a new server, what is insecure, or you could give it a list of known secure servers. In this case
ypbind
will send a ping to all servers and binds to first one which answers.
Unless the option
-debug
is used, ypbind detaches itself from the controlling terminal and puts itself into background.
ypbind
uses
syslog(3)
for logging errors and warnings. At startup or when receiving signal SIGHUP,
ypbind
parses the file
/etc/yp.conf
and tries to use the entries for its initial binding.
A broadcast entry in the configuration file will overwrite a ypserver/server entry and a ypserver/server entry broadcast. If all given server are down,
ypbind
will
not
switch to use broadcast.
ypbind
will try at first
/etc/hosts
and then
DNS
for resolving the hosts names from
/etc/yp.conf. If
ypbind
couldn't reconfigure the search order, it will use only
DNS. If
DNS
isn't available, you could only use IP-addresses in
/etc/hosts.
ypbind
could only reconfigure the search order with glibc 2.x. If the
-broadcast
option is specified,
ypbind
will ignore the configuration file. If the file does not exist or if there are no valid entries,
ypbind
exit.
This
ypbind
version listens for DBUS messages from NetworkManager. If no NetworkManager is running at startup,
ypbind
will behave as usual and assumes there is a working network connection. If NetworkManager is running on the system, ypbind will only search and providde NIS informations, if NetworkManager tells that a network connection is available. If NetworkManager establishes a connection,
ypbind
will reread all configuration files, registers at the local portmapper and try to search NIS servers. If NetworkManager drops a connection,
ypbind
will unregister from portmapper.
OPTIONS
- -broadcast
-
Send a broadcast to request the information needed to bind to a specific NIS server. With this option,
/etc/yp.conf
will be ignored.
- -ypset
-
Allow
root
from any remote machine to change the binding for a domain via the
ypset(8)
command. By default, no one can change the binding. This option is really insecure. If you change a binding for a domain, all the current known servers for this domain will be forgotten. If the new server goes down,
ypbind
will use the old searchlist.
- -ypsetme
-
The same as
-ypset, but only
root
on the local machine is allowed to chang the binding. Such requests are only allowd from
loopback.
- -c
-
ypbind
only checks if the config file has syntax errors and exits.
- -debug
-
starts
ypbind
in debug mode.
ypbind
will not put itself into background, and error messages and debug output are written to standard error.
- -verbose
-
Causes
ypbind
to syslog(2) any and all changes in the server its bound to.
- -broken-server
-
lets
ypbind
accept answers from servers running on an illegal port number. This should usually be avoided, but is required by some
ypserv(8)
versions.
- -no-ping
-
ypbind
will not check if the binding is alive. This option is for use with dialup connections to prevent
ypbind
from keeping the connection unnessecarily open or causing autodials.
- -p port
-
ypbind
will bind itself to this port.
This makes it possible to have a router filter packets
to the NIS ports, so that access to this service from
hosts on the Internet can be restricted.
- -f configfile
-
ypbind
will use
configfile
and not
/etc/yp.conf
- -local-only
-
ypbind
will only bind to the loopback device and is not reacheable from a remote network.
- -ping-interval ping-interval
-
The default value for
ypbind
to check, if a NIS server is still reacheable, is 20 seconds. With this options another frequency in seconds can be specified.
- -no-dbus
-
Disables DBUS support if compiled in.
- --version
-
Prints the version number
FILES
- /etc/yp.conf
-
configuration file.
- /var/yp/binding/[domainname].[version]
-
binding file containing information about each NIS domain.
- /var/run/ypbind.pid
-
contains the process id of the currently running
ypbind
master process.
SEE ALSO
syslog(3),
domainname(1),
yp.conf(5),
ypdomainname(8),
ypwhich(1),
ypserv(8),
ypset(8)
AUTHOR
ypbind-mt
was written by Thorsten Kukuk <kukuk@thkukuk.de>.