1YPSERV(8)                    NIS Reference Manual                    YPSERV(8)
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NAME

6       ypserv - NIS Server
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SYNOPSIS

9       /usr/sbin/ypserv [-d [path]] [-p port]
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DESCRIPTION

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.
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16       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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OPTIONS

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
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33       -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.
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38       -v, --version
39           Prints the version number
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SECURITY

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.
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51       A sample securenets file might look like this:
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54               # 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
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66       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.
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71       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.
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77       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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BUGS

83       Sending the signal SIGHUP to the server can lead to a deadlock or
84       crash.
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FILES

87       /etc/ypserv.conf
88           configuration file.
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90       /var/yp/securenets
91           which hosts are allowed to contact ypserv.
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SEE ALSO

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)
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98       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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AUTHOR

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.
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111NIS Reference Manual              01/27/2010                         YPSERV(8)
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