YPBIND(8) ypbind-mt YPBIND(8)NAMEypbind - NIS binding process
SYNOPSISypbind [-broadcast | -ypset | -ypsetme] [-c] [-f configfile] [-no-ping]
[-broken-server] [-local-only]
[-i | -ping-interval ping-interval]
[-r | -rebind-interval rebind-interval] [-d | -debug]
[-v | -verbose] [-n | -foreground] [-p port] [-log log-options]
[-no-dbus]
ypbind--version
ypbind--help
DESCRIPTIONypbind finds the server for NIS domains and maintains the NIS binding
information. The client (normally 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 provide 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.
In Fedora we use systemd for starting services. We need to finish
starting process of ypbind service not before service is fully started,
which means ypbind daemon is prepared to answer. There is a test script
/usr/libexec/ypbind-post-waitbind used in ypbind.service, that waits
for ypbind daemon to be fully connected to NIS server and waits by
default up to 45s. Sometimes this is not enough, because network set up
can take longer than 45s during boot, so starting ypbind.service fails.
User can increase the timeout by setting an environment variable
NISTIMEOUT in /etc/sysconfig/ypbind. For example NISTIMEOUT=180 means
ypbind will wait up to 180 seconds for binding to a NIS server.
Another option is to enable NetworkManager-wait-online.service and add
an ordering rule into ypbind.service, ideally by creating
/etc/systemd/system/ypbind.service with the following content:
.include /lib/systemd/system/ypbind.service
[Service]
After=NetworkManager-wait-online.service
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 change the binding. Such requests are only allowed from
loopback.
-c
ypbind only checks if the config file has syntax errors and exits.
-d, -debug
starts ypbind in debug mode. ypbind will not put itself into
background, and error messages and debug output are written to
standard error.
-n, -foreground
ypbind will not put itself into backgroun.
-v, -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 unnecessarily open or causing auto-dials.
-f configfile
ypbind will use configfile and not /etc/yp.conf
-local-only
ypbind will only bind to the loopback device and is not reachable
from a remote network.
-p port
Lets ypbind listen on a specified port number, rather than asking
portmapper to assing a port for it.
-i, -ping-interval ping-interval
The default value for ypbind to check, if a NIS server is still
reachable, is 20 seconds. With this options another frequency in
seconds can be specified.
-r, -rebind-interval rebind-interval
The default value for ypbind to search for the fastest NIS server
is 900 seconds (15 minutes). With this options another frequency in
seconds can be specified.
-log log-options
Allows to log special events. log-options is a logical sum of
values for particular events - 1 for logging rpc calls, 2 for
logging broken server calls, 4 for logging server changes.
-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 ALSOsyslog(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>.
ypbind-mt 04/09/2013 YPBIND(8)
