1YPBIND(8) ypbind-mt YPBIND(8)
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6 ypbind - NIS binding process
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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]
13 ypbind -c [-f configfile]
15 ypbind --version
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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 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.
36 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.
42 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.
53 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 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:
73 [Service]
75 Before=foo.service
76 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 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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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.
96 -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 -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.
109 -c
111 ypbind only checks if the config file has syntax errors and exits.
112 -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.
117 -n, -foreground
119 ypbind will not put itself into backgroun.
120 -v, -verbose
122 Causes ypbind to syslog(2) any and all changes in the server its
123 bound to.
124 -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 -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 -f configfile
136 ypbind will use configfile and not /etc/yp.conf
137 -local-only
139 ypbind will only bind to the loopback device and is not reachable
140 from a remote network.
141 -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.
146 -p port
148 Lets ypbind listen on a specified port number, rather than asking
149 portmapper to assingn a port for it.
150 --version
152 Prints the version number
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155 /etc/yp.conf
156 configuration file.
157 /var/yp/binding/[domainname].[version]
159 binding file containing information about each NIS domain.
160 /var/run/ypbind.pid
162 contains the process id of the currently running ypbind master
163 process.
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166 syslog(3), domainname(1), yp.conf(5), ypdomainname(8), ypwhich(1),
167 ypserv(8), ypset(8)
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170 ypbind-mt was written by Thorsten Kukuk <kukuk@thkukuk.de>.
171ypbind-mt 01/28/2021 YPBIND(8)