1YPSERV(8) NIS Reference Manual YPSERV(8)
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6 ypserv - NIS Server
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9 /usr/sbin/ypserv [-d [path]] [-p port]
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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 [path]
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. path is an optionally parameter. ypserv is
33 using this directory instead of /var/yp
34 -p, --port port
36 ypserv will bind itself to this port. This makes it possible to
37 have a router filter packets to the NIS ports, so that access to
38 the NIS server from hosts on the Internet can be restricted.
39 -v, --version
41 Prints the version number
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44 In general, any remote user can issue an RPC to ypserv and retrieve the
45 contents of your NIS maps, if he knows your domain name. To prevent
46 such unauthorized transactions, ypserv supports a feature called
47 securenets which can be used to restrict access to a given set of
48 hosts. At startup ypserv will attempt to load the securenets
49 information from a file called /var/yp/securenets . This file contains
50 entries that consist of a netmask and a network pair separated by white
51 spaces or network/number of bits of netmask entries. One per line.
52 Lines starting with “#” are considered to be comments.
53 A sample securenets file might look like this:
55 # allow connections from local host -- necessary
57 host 127.0.0.1
58 host ::1
59 # same as 255.255.255.255 127.0.0.1
60 #
61 # allow connections from any host
62 # on the 131.234.223.0 network
63 255.255.255.0 131.234.223.0
64 # allow connections from any host
65 # between 131.234.214.0 and 131.234.215.255
66 255.255.254.0 131.234.214.0
67 # allow some IPv6 connections
68 FE80::0202:B3FF::/96
69 # allow IPv6 connections from all machines
70 ::/0
71 If ypserv receives a request from an address that fails to match a
74 rule, the request will be ignored and a warning message will be logged.
75 If the /var/yp/securenets file does not exist, ypserv will allow
76 connections from any host.
77 In the /etc/ypserv.conf you could specify some access rules for special
79 maps and hosts. But it is not very secure, it makes the life only a
80 little bit harder for a potential hacker. If a mapname doesn't match a
81 rule, ypserv will look for the YP_SECURE key in the map. If it exists,
82 ypserv will only allow requests on a reserved port.
83 For security reasons, ypserv will only accept ypproc_xfr requests for
85 updating maps from the same master server as the old one. This means,
86 you have to reinstall the slave servers if you change the master server
87 for a map.
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90 /etc/ypserv.conf
91 configuration file.
92 /var/yp/securenets
94 which hosts are allowed to contact ypserv.
95 /etc/sysconfig/network
97 setting additional arguments to ypserv.
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100 domainname(1), ypcat(1), ypmatch(1), ypserv.conf(5), netgroup(5),
101 makedbm(8), revnetgroup(8), ypinit(8), yppoll(8), yppush(8), ypset(8),
102 ypwhich(8), ypxfr(8), rpc.ypxfrd(8)
103 The Network Information Service (NIS) was formerly known as Sun Yellow
105 Pages (YP). The functionality of the two remains the same; only the
106 name has changed. The name Yellow Pages is a registered trademark in
107 the United Kingdom of British Telecommunications plc, and may not be
108 used without permission.
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111 ypserv was written by Peter Eriksson <pen@lysator.liu.se>. Thorsten
112 Kukuk <kukuk@linux-nis.org> added support for master/slave server and
113 is the new Maintainer.
114NIS Reference Manual 01/31/2020 YPSERV(8)