From 230b023a13d3e5604973eb910ee941cbf72e0474 Mon Sep 17 00:00:00 2001 From: jmg Date: Tue, 15 Apr 1997 07:41:10 +0000 Subject: fix some typos, and some slight clean up... Closes PR#3266 --- usr.sbin/ypserv/ypserv.8 | 105 +++++++++++++++++++++++++---------------------- 1 file changed, 57 insertions(+), 48 deletions(-) (limited to 'usr.sbin/ypserv') diff --git a/usr.sbin/ypserv/ypserv.8 b/usr.sbin/ypserv/ypserv.8 index d3b0114..69cf0ae 100644 --- a/usr.sbin/ypserv/ypserv.8 +++ b/usr.sbin/ypserv/ypserv.8 @@ -28,21 +28,21 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.\" $Id$ +.\" $Id: ypserv.8,v 1.11 1997/02/22 16:15:14 peter Exp $ .\" .Dd February 4, 1995 .Dt YPSERV 8 .Os .Sh NAME .Nm ypserv -.Nd "NIS database server" +.Nd NIS database server .Sh SYNOPSIS -.Nm ypserv +.Nm .Op Fl n .Op Fl d .Op Fl p Ar path .Sh DESCRIPTION -.Nm NIS +.Tn NIS is an RPC-based service designed to allow a number of UNIX-based machines to share a common set of configuration files. Rather than requiring a system administrator to update several copies of files @@ -55,13 +55,14 @@ which tend to require frequent changes in most environments, NIS allows groups of computers to share one set of data which can be updated from a single location. .Pp -.Nm ypserv -is the server that distributes NIS databases +The +.Nm +program is the server that distributes NIS databases to client systems within an NIS -.Nm domain. +.Em domain . Each client in an NIS domain must have its domainname set to one of the domains served by -.Nm ypserv +.Nm using the .Xr domainname 1 command. The clients must also run @@ -70,21 +71,21 @@ in order to attach to a particular server, since it is possible to have several servers within a single NIS domain. .Pp The databases distributed by -.Nm ypserv +.Nm are stored in .Pa /var/yp/[domainname] where .Pa domainname is the name of the domain being served. There can be several such directories with different domainnames, and you need only one -.Nm ypserv +.Nm daemon to handle them all. .Pp The databases, or .Pa maps as they are often called, are created by -.Nm /var/yp/Makefile +.Pa /var/yp/Makefile using several system files as source. The database files are in .Xr db 3 format to help speed retrieval when there are many records involved. @@ -95,11 +96,12 @@ maps, but since the data in the other maps can be found in other world-readable files anyway, it doesn't hurt and it's considered good general practice. .Pp -.Nm ypserv -is started by -.Nm /etc/rc +The +.Nm +program is started by +.Pa /etc/rc if it has been enabled in -.Nm /etc/sysconfig. +.Pa /etc/sysconfig . .Sh SPECIAL FEATURES There are some problems associated with distributing FreeBSD's password database via NIS: FreeBSD normally only stores encrypted passwords @@ -109,7 +111,7 @@ which is readable and writable only by root. By turning this file into an NIS map, this security feature would be completely defeated. .Pp To make up for this, the FreeBSD version of -.Nm ypserv +.Nm handles the .Pa master.passwd.byname and @@ -135,7 +137,7 @@ the standard and .Pa passwd.byuid maps will be accessed instead. The latter two maps are constructed by -.Nm /var/yp/Makefile +.Pa /var/yp/Makefile by parsing the .Pa master.passwd file and stripping out the password fields, and are therefore @@ -151,16 +153,18 @@ that users should be aware of: .Bl -enum -offset indent .It -The 'TCP port less than 1024' test is trivial to defeat for users with +The +.Sq TCP port less than 1024 +test is trivial to defeat for users with unrestricted access to machines on your network (even those machines which do not run UNIX-based operating systems). .It If you plan to use a FreeBSD system to serve non-FreeBSD clients that have no support for password shadowing (which is most of them), you will have to disable the password shadowing entirely by uncommenting the -.Nm UNSECURE=True +.Em UNSECURE=True entry in -.Nm /var/yp/Makefile . +.Pa /var/yp/Makefile . This will cause the standard .Pa passwd.byname and @@ -172,25 +176,27 @@ authentication through NIS. .Pp .Ss Security In general, any remote user can issue an RPC to -.Nm ypserv +.Nm and retrieve the contents of your NIS maps, provided the remote user knows your domain name. To prevent such unauthorized transactions, -.Nm ypserv +.Nm supports a feature called .Pa securenets which can be used to restrict access to a given set of hosts. At startup, -.Nm ypserv +.Nm will attempt to load the securenets information from a file called -.Nm /var/yp/securenets . +.Pa /var/yp/securenets . (Note that this path varies depending on the path specified with the .Fl p option, which is explained below.) This file contains entries that consist of a network specification and a network mask separated by white space. -Lines starting with ``#'' are considered to be comments. A +Lines starting with +.Dq \&# +are considered to be comments. A sample securenets file might look like this: .Bd -unfilled -offset indent # allow connections from local host -- mandatory @@ -204,28 +210,29 @@ sample securenets file might look like this: .Ed .Pp If -.Nm ypserv +.Nm receives a request from an address that matches one of these rules, it will process the request normally. If the address fails to match a rule, the request will be ignored and a warning message will be logged. If the .Pa /var/yp/securenets file does not exist, -.Nm ypserv +.Nm will allow connections from any host. .Pp -.Nm Ypserv -also has support for Wietse Venema's -.Pa tcpwrapper +The +.Nm +program also has support for Wietse Venema's +.Em tcpwrapper package, though it is not compiled in by default since the -.Pa tcpwrapper +.Em tcpwrapper package is not distributed with FreeBSD. However, if you have -.Nm libwrap.a +.Pa libwrap.a and -.Nm tcpd.h , +.Pa tcpd.h , you can easily recompile -.Nm ypserv +.Nm with them. This allows the administrator to use the tcpwrapper configuration files ( .Pa /etc/hosts.allow @@ -236,11 +243,13 @@ for access control instead of .Pp Note: while both of these access control mechanisms provide some security, they, like the privileged port test, are both vulnerable -to ``IP spoofing'' attacks. +to +.Dq IP spoofing +attacks. .Pp .Ss NIS v1 compatibility This version of -.Nm ypserv +.Nm has some support for serving NIS v1 clients. FreeBSD's NIS implementation only uses the NIS v2 protocol, however other implementations include support for the v1 protocol for backwards compatibility @@ -252,14 +261,14 @@ server even though they may never actually need it (and they may persist in broadcasting in search of one even after they receive a response from a v2 server). Note that while support for normal client calls is provided, this version of -.Nm ypserv +.Nm does not handle v1 map transfer requests; consequently, it can not be used as a master or slave in conjunction with older NIS servers that only support the v1 protocol. Fortunately, there probably aren't any such servers still in use today. .Ss NIS servers that are also NIS clients Care must be taken when running -.Nm ypserv +.Nm in a multi-server domain where the server machines are also NIS clients. It is generally a good idea to force the servers to bind to themselves rather than allowing them to broadcast bind @@ -276,26 +285,26 @@ man page for details on how to force it to bind to a particular server. .Sh OPTIONS The following options are supported by -.Nm ypserv : +.Nm Ns : .Bl -tag -width flag .It Fl n This option affects the way -.Nm ypserv +.Nm handles yp_match requests for the .Pa hosts.byname and .Pa hosts.byaddress maps. By default, if -.Nm ypserv +.Nm can't find an entry for a given host in its hosts maps, it will return an error and perform no further processing. With the .Fl n flag, -.Nm ypserv +.Nm will go one step further: rather than giving up immediately, it will try to resolve the hostname or address using a DNS nameserver query. If the query is successful, -.Nm ypserv +.Nm will construct a fake database record and return it to the client, thereby making it seem as though the client's yp_match request succeeded. @@ -308,14 +317,14 @@ queries directly, therefore it is not necessary to enable this option when serving only FreeBSD NIS clients. .It Fl d Causes the server to run in debugging mode. Normally, -.Nm ypserv +.Nm reports only unusual errors (access violations, file access failures) using the .Xr syslog 3 facility. In debug mode, the server does not background itself and prints extra status messages to stderr for each -request that it revceives. Also, while running in debug mode, -.Nm ypserv +request that it receives. Also, while running in debug mode, +.Nm will not spawn any additional subprocesses as it normally does when handling yp_all requests or doing DNS lookups. (These actions often take a fair amount of time to complete and are therefore handled @@ -324,7 +333,7 @@ other requests.) This makes it easier to trace the server with a debugging tool. .It Fl p Ar path Normally, -.Nm ypserv +.Nm assumes that all NIS maps are stored under .Pa /var/yp . The @@ -354,6 +363,6 @@ Host access control file Bill Paul .Sh HISTORY This version of -.Nm ypserv +.Nm first appeared in .Fx 2.2 . -- cgit v1.1