1YPBIND(8)                          ypbind-mt                         YPBIND(8)
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NAME

6       ypbind - NIS binding process
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SYNOPSIS

9       ypbind [-broadcast | -ypset | -ypsetme] [-f configfile] [-no-ping]
10              [-broken-server] [-local-only] [-ping-interval ping-interval |
11              -i ping-interval] [-d | -debug] [-v | -verbose] [-n |
12              -foreground] [-p port]
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14       ypbind -c [-f configfile]
15
16       ypbind --version
17

DESCRIPTION

19       ypbind finds the server for NIS domains and maintains the NIS binding
20       information. The client (normally the NIS routines in the standard C
21       library) could get the information over RPC from ypbind or read the
22       binding files. The binding files resides in the directory
23       /var/yp/binding and are conventionally named [domainname].[version].
24       The supported versions are 1, 2 and 3. There could be several such
25       files since it is possible for an NIS client to be bound to more than
26       one domain.
27
28       After a binding has been established, ypbind will send YPPROC_DOMAIN
29       requests to the current NIS server at 5 minutes intervals. If it
30       doesn't get an response or the NIS server reports that he doesn't have
31       this domain any longer, ypbind will search for a new NIS server. You
32       could tell ypbind to use network broadcasts to find a new server, what
33       is insecure, or you could give it a list of known secure servers. In
34       this case ypbind will send a ping to all servers in the order in which
35       they are listed in the config file and use the first one which answers.
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37       Unless the option -debug or -foreground is used, ypbind detaches itself
38       from the controlling terminal and puts itself into background.  ypbind
39       uses syslog(3) for logging errors and warnings. At startup or when
40       receiving signal SIGHUP, ypbind parses the file /etc/yp.conf and tries
41       to use the entries for its initial binding.
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43       A broadcast entry in the configuration file will overwrite a
44       ypserver/server entry and a ypserver/server entry broadcast. If all
45       given server are down, ypbind will not switch to use broadcast.  ypbind
46       will try at first /etc/hosts and then DNS for resolving the hosts names
47       from /etc/yp.conf. If ypbind couldn't reconfigure the search order, it
48       will use only DNS. If DNS isn't available, you could only use
49       IP-addresses in /etc/hosts.  ypbind could only reconfigure the search
50       order with glibc 2.x. If the -broadcast option is specified, ypbind
51       will ignore the configuration file. If the file does not exist or if
52       there are no valid entries, ypbind exit.
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54       In Fedora we use systemd for starting services. We need to finish
55       starting process of ypbind service not before service is fully started,
56       which means ypbind daemon is prepared to answer. There is a test script
57       /usr/libexec/ypbind-post-waitbind used in ypbind.service, that waits
58       for ypbind daemon to be fully connected to NIS server and waits by
59       default up to 45s. Sometimes this is not enough, because network set up
60       can take longer than 45s during boot, so starting ypbind.service fails.
61       User can increase the timeout by setting an environment variable
62       NISTIMEOUT in /etc/sysconfig/ypbind. For example NISTIMEOUT=180 means
63       ypbind will wait up to 180 seconds for binding to a NIS server. Another
64       option is to enable NetworkManager-wait- online.service, which will
65       make ypbind to wait until network is properly set up.
66
67       In case something needs to be changed in the ypbind.service, it is
68       adviced not to change the ypbind.service directly, but rather to create
69       a new file under /etc/systemd/system/ypbind.service.d/, i.e. if we need
70       to start ypbind before service foo.service, we can create file
71       /etc/systemd/system/ypbind.service.d/wait-foo.conf with the following
72       content:
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74           [Service]
75           Before=foo.service
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77       If you need to pass other arguments to ypbind daemon withing systemd
78       unit file, you can set these arguments as OTHER_YPBIND_OPTS environment
79       variable in /etc/sysconfig/ypbind. For example in order to set a fixed
80       port ypbind should run on, you can specify OTHER_YPBIND_OPTS="-p 876"
81       in /etc/sysconfig/ypbind.
82
83       DHCP client by defualt changes /etc/yp.conf in case DHCP server sends
84       NIS configuration in the respond. In that case
85       /etc/dhcp/dhclient.d/nis.sh changes /etc/yp.conf according such
86       configuration and creates a back-up copy of the original configuration
87       file into /var/lib/dhclient/nis.conf.predhclient.$interface. In order
88       to disable changing /etc/yp.conf by DHCP client, add PEERNIS=no into
89       /etc/sysconfig/network.
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OPTIONS

92       -broadcast
93           Send a broadcast to request the information needed to bind to a
94           specific NIS server. With this option, /etc/yp.conf will be
95           ignored.
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97       -ypset
98           Allow root from any remote machine to change the binding for a
99           domain via the ypset(8) command. By default, no one can change the
100           binding. This option is really insecure. If you change a binding
101           for a domain, all the current known servers for this domain will be
102           forgotten. If the new server goes down, ypbind will use the old
103           searchlist.
104
105       -ypsetme
106           The same as -ypset, but only root on the local machine is allowed
107           to change the binding. Such requests are only allowed from
108           loopback.
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110       -c
111           ypbind only checks if the config file has syntax errors and exits.
112
113       -d, -debug
114           starts ypbind in debug mode.  ypbind will not put itself into
115           background, and error messages and debug output are written to
116           standard error.
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118       -n, -foreground
119           ypbind will not put itself into backgroun.
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121       -v, -verbose
122           Causes ypbind to syslog(2) any and all changes in the server its
123           bound to.
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125       -broken-server
126           Lets ypbind accept answers from servers running on an illegal port
127           number. This should usually be avoided, but is required by some
128           ypserv(8) versions.
129
130       -no-ping
131           ypbind will not check if the binding is alive. This option is for
132           use with dialup connections to prevent ypbind from keeping the
133           connection unnecessarily open or causing auto-dials.
134
135       -f configfile
136           ypbind will use configfile and not /etc/yp.conf
137
138       -local-only
139           ypbind will only bind to the loopback device and is not reachable
140           from a remote network.
141
142       -i, -ping-interval ping-interval
143           The default value for ypbind to check, if a NIS server is still
144           reachable, is 20 seconds. With this options another frequency in
145           seconds can be specified.
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147       -p port
148           Lets ypbind listen on a specified port number, rather than asking
149           portmapper to assingn a port for it.
150
151       --version
152           Prints the version number
153

FILES

155       /etc/yp.conf
156           configuration file.
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158       /var/yp/binding/[domainname].[version]
159           binding file containing information about each NIS domain.
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161       /var/run/ypbind.pid
162           contains the process id of the currently running ypbind master
163           process.
164

SEE ALSO

166       syslog(3), domainname(1), yp.conf(5), ypdomainname(8), ypwhich(1),
167       ypserv(8), ypset(8)
168

AUTHOR

170       ypbind-mt was written by Thorsten Kukuk <kukuk@thkukuk.de>.
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174ypbind-mt                         05/14/2019                         YPBIND(8)
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