ypbind - NIS binding process
SYNOPSIS
ypbind [ -c ] [ -d|-debug ] [ -broadcast ] [ -broken-
server ] [ -ypset ] [ -ypsetme ] [ -no-ping ] [ -p port ][
-f configfile ]
ypbind --version
DESCRIPTION
ypbind finds the server for NIS domains and maintains the
NIS binding information. The client (normaly the NIS rou
tines in the standard C library) could get the information
over RPC from ypbind or read the binding files. The bind
ing files resides in the directory /var/yp/binding and are
conventionally named [domainname].[version]. The sup
ported versions are 1 and 2. There could be serveral such
files since it is possible for an NIS client to be bound
to more then 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 tells that he doesn't has this domain any
longer, ypbind will search a new NIS server. All 15 min
utes ypbind will check, 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 net
work 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 server and binds
to first one which answers.
Unless the option -debug is used, ypbind detaches itself
from the controlling terminal and puts itself into back
ground. ypbind uses 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. Valid entries are
domain nisdomain server hostname
Use server hostname for the domain nisdomain. You
could have more then one entry of this type for a
single domain.
domain nisdomain broadcast
Use broadcast on the local net for domain nisdo
main.
ypserver hostname
Use server server for the local domain.
A broadcast entry in the configuration file will overwrite
cast. 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 is a special version which uses pthreads. It
will start 2 more threads. The master process services
RPC requests asking for binding info. The first thread
initializes the binding and checks it periodically. Upon
failure, the binding is invalidated and the process tries
again to find a valid server. The second thread will han
dle all the signals.
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.
-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) ver
sions.
ypbind will not check if the binding is alive. This
option is for use with dialup connections to pre
vent ypbind from keeping the connection unnessecar
ily open or causing autodials.
-f configfile
ypbind will use configfile and not /etc/yp.conf
-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.
--version
Prints the version number
NOTES
Binding to multiple domains is tested and works. Load
sharing between multiple servers for a single domain is
not supported. ypbind will always try to bind a domain to
a server. If there is no valid server in the list or
answers to a broadcast, the domain is unbounded.
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), ypwhich(1), ypserv(8), ypset(8)
AUTHOR
ypbind-mt was written by Thorsten Kukuk <kukuk@suse.de>.
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