1YPSERV(8) NIS Reference Manual YPSERV(8)
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6 ypserv - NIS Server
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9 /usr/sbin/ypserv [-d] [-p port] [-f|--foreground]
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12 The Network Information Service (NIS) provides a simple network lookup
13 service consisting of databases and processes. The databases are gdbm
14 files in a directory tree rooted at /var/yp.
15 The ypserv daemon is typically activated at system startup. ypserv
17 runs only on NIS server machines with a complete NIS database. On other
18 machines using the NIS services, you have to run ypbind as client or
19 under Linux you could use the libc with NYS support. ypbind must run
20 on every machine which has NIS client processes; ypserv may or may not
21 be running on the same node, but must be running somewhere on the
22 network. On startup ypserv parses the file /etc/ypserv.conf. It is
23 also possible to pass OPTIONS to ypserv using the environment variable
24 YPSERV_ARGS and this variable can be set in /etc/sysconfig/network.
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27 -d, --debug
28 Causes the server to run in debugging mode. Normally, ypserv
29 reports only errors (access violations, dbm failures) using the
30 syslog(3) facility. In debug mode, the server does not background
31 itself and prints extra status messages to stderr for each request
32 that it revceives.
33 -p, --port port
35 ypserv will bind itself to this port. This makes it possible to
36 have a router filter packets to the NIS ports, so that access to
37 the NIS server from hosts on the Internet can be restricted.
38 -v, --version
40 Prints the version number
41 -f, --foreground
43 will not put itself into background.
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46 In general, any remote user can issue an RPC to ypserv and retrieve the
47 contents of your NIS maps, if he knows your domain name. To prevent
48 such unauthorized transactions, ypserv supports a feature called
49 securenets which can be used to restrict access to a given set of
50 hosts. At startup ypserv will attempt to load the securenets
51 information from a file called /var/yp/securenets . This file contains
52 entries that consist of a netmask and a network pair separated by white
53 spaces. Lines starting with “#” are considered to be comments.
54 A sample securenets file might look like this:
56 # allow connections from local host -- necessary
59 host 127.0.0.1
60 # same as 255.255.255.255 127.0.0.1
61 #
62 # allow connections from any host
63 # on the 131.234.223.0 network
64 255.255.255.0 131.234.223.0
65 # allow connections from any host
66 # between 131.234.214.0 and 131.234.215.255
67 255.255.254.0 131.234.214.0
68 If ypserv receives a request from an address that fails to match a
71 rule, the request will be ignored and a warning message will be logged.
72 If the /var/yp/securenets file does not exist, ypserv will allow
73 connections from any host.
74 In the /etc/ypserv.conf you could specify some access rules for special
76 maps and hosts. But it is not very secure, it makes the life only a
77 little bit harder for a potential hacker. If a mapname doesn´t match a
78 rule, ypserv will look for the YP_SECURE key in the map. If it exists,
79 ypserv will only allow requests on a reserved port.
80 For security reasons, ypserv will only accept ypproc_xfr requests for
82 updating maps from the same master server as the old one. This means,
83 you have to reinstall the slave servers if you change the master server
84 for a map.
85
87 Sending the signal SIGHUP to the server can lead to a deadlock or
88 crash.
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91 /etc/ypserv.conf
92 configuration file.
93 /var/yp/securenets
95 which hosts are allowed to contact ypserv.
96 /etc/sysconfig/network
98 setting additional arguments to ypserv.
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101 domainname(1), ypcat(1), ypmatch(1), ypserv.conf(5), netgroup(5),
102 makedbm(8), revnetgroup(8), ypinit(8), yppoll(8), yppush(8), ypset(8),
103 ypwhich(8), ypxfr(8), rpc.ypxfrd(8)
104 The Network Information Service (NIS) was formerly known as Sun Yellow
106 Pages (YP). The functionality of the two remains the same; only the
107 name has changed. The name Yellow Pages is a registered trademark in
108 the United Kingdom of British Telecommunications plc, and may not be
109 used without permission.
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112 ypserv was written by Peter Eriksson <pen@lysator.liu.se>. Thorsten
113 Kukuk <kukuk@linux-nis.org> added support for master/slave server and
114 is the new Maintainer.
115NIS Reference Manual 01/27/2010 YPSERV(8)