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.
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25 -d, --debug [path]
26 Causes the server to run in debugging mode. Normally, ypserv
27 reports only errors (access violations, dbm failures) using the
28 syslog(3) facility. In debug mode, the server does not background
29 itself and prints extra status messages to stderr for each request
30 that it revceives. path is an optionally parameter. ypserv is
31 using this directory instead of /var/yp
32 -p, --port port
34 ypserv will bind itself to this port. This makes it possible to
35 have a router filter packets to the NIS ports, so that access to
36 the NIS server from hosts on the Internet can be restricted.
37 -v, --version
39 Prints the version number
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42 In general, any remote user can issue an RPC to ypserv and retrieve the
43 contents of your NIS maps, if he knows your domain name. To prevent
44 such unauthorized transactions, ypserv supports a feature called
45 securenets which can be used to restrict access to a given set of
46 hosts. At startup ypserv will attempt to load the securenets
47 information from a file called /var/yp/securenets . This file contains
48 entries that consist of a netmask and a network pair separated by white
49 spaces. Lines starting with “#” are considered to be comments.
50 A sample securenets file might look like this:
52 # allow connections from local host -- necessary
55 host 127.0.0.1
56 # same as 255.255.255.255 127.0.0.1
57 #
58 # allow connections from any host
59 # on the 131.234.223.0 network
60 255.255.255.0 131.234.223.0
61 # allow connections from any host
62 # between 131.234.214.0 and 131.234.215.255
63 255.255.254.0 131.234.214.0
64 If ypserv receives a request from an address that fails to match a
67 rule, the request will be ignored and a warning message will be logged.
68 If the /var/yp/securenets file does not exist, ypserv will allow
69 connections from any host.
70 In the /etc/ypserv.conf you could specify some access rules for special
72 maps and hosts. But it is not very secure, it makes the life only a
73 little bit harder for a potential hacker. If a mapname doesn´t match a
74 rule, ypserv will look for the YP_SECURE key in the map. If it exists,
75 ypserv will only allow requests on a reserved port.
76 For security reasons, ypserv will only accept ypproc_xfr requests for
78 updating maps from the same master server as the old one. This means,
79 you have to reinstall the slave servers if you change the master server
80 for a map.
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83 Sending the signal SIGHUP to the server can lead to a deadlock or
84 crash.
85
87 /etc/ypserv.conf
88 configuration file.
89 /var/yp/securenets
91 which hosts are allowed to contact ypserv.
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94 domainname(1), ypcat(1), ypmatch(1), ypserv.conf(5), netgroup(5),
95 makedbm(8), revnetgroup(8), ypinit(8), yppoll(8), yppush(8), ypset(8),
96 ypwhich(8), ypxfr(8), rpc.ypxfrd(8)
97 The Network Information Service (NIS) was formerly known as Sun Yellow
99 Pages (YP). The functionality of the two remains the same; only the
100 name has changed. The name Yellow Pages is a registered trademark in
101 the United Kingdom of British Telecommunications plc, and may not be
102 used without permission.
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105 ypserv was written by Peter Eriksson <pen@lysator.liu.se>. Thorsten
106 Kukuk <kukuk@linux-nis.org> added support for master/slave server and
107 is the new Maintainer.
108NIS Reference Manual 01/27/2010 YPSERV(8)