# Copyright (c) 1992 by Texas Internet Consulting
# This code may be freely copied and used so long as this
# copyright notice is attached.  This code may not be sold
# without the express written permission of Texas Internet Consulting.
# Texas Internet Consulting makes no warranty as to the correctness
# nor the applicability of this code for any purpose.

Generic host configuration files.

This is a brief overview of a set of utilities used to manage
host files when running DNS or NIS nameservice or both.

File description:

README - this file
etc.named - files installed in /etc/named
gendns - shell script to generate DNS tables
genstatic - shell script to generate static host file
make_rev - automatically creates the reverse DNS map
poke_ns.c - C program to help manage DNS servers
readinfo - shell script to extract fields from hst files
updatehosts - shell scrip to automate host update

This host database system organizes host information in a set of
flat tables.  All host updates are made in these tables.  From these
tables both the static host table and the DNS database files are created.
This eliminates potential errors caused by having to maintain two sets of
host tables.

The static host table is used to update NIS maps, if you run NIS.  It can
also be used on machines which may not have DNS or NIS support.

Install the scripts in /usr/local/etc.  Compile and install poke_ns in
/usr/local/etc making it setuid to root, but only executable by the group
of users which will be maintainingg the host database.  Do not make it
executable by everyone.  Check the define NAMED and be sure it points to
the pathname for your nameserver.

The next step is to install the files in etc.named in the /etc/named
directory or the directory where the DNS database files will be maintained.

Now populate the host database files.  These files are organized like a
relational database and consist of several files.  They are all under SCCS
control and must be checked out to be populated.  Be sure and check the
files back in under SCCS before continuing.

hosts.main - the main host file.  Required fields are the host and IP
address field.  Note the #FIELDS line.  This describes the fields to the
readinfo script which extracts particular fields from the host.* files.
Each field is described by its fieldname, followed by an optional prefix=,
suffix=, or no= descriptor.  The prefix= and suffix= describe what will be
prepended or appended to the field value when readinfo outputs the field.
For host names the suffix is equal to the default domain.  For host
addresses the prefix is equal to the network number.  This facility is a
useful shorthand.  The no= field gives a character which says to display
the host value as given and ignore any prefix or suffix.  For example if
your default domain is tic.com and you have a host named tic.com enter it
in the file as @tic.com@.

hosts.cname - host alias file.  This has two fields the real host name
followed an alias for the host.  If a host has more than a single alias,
renteer the host name followed by the second alias.

hosts.mx - DNS MX information is entered here.  This file has three fields:
the domain name to MX for, the priority of the MX record and the host to
forward mail to for this domain.

The other hosts.* and remaining files are helper files
for creating the static host tables and DNS files.  No data needs to be entered into them.

Create a file in nisservers of the host names for NIS servers for doing
host lookups.  If you have no NIS servers performing this function do not
create this file.

Run the command updatehosts -u.  This will generate the DNS tables and
start the DNS server or cause the currently running server to reload its
data files.  If you are replacing an existing DNS server it is best to
bring it down first  before typing this command.  When you update the host
files in the future, type updatehosts followed by the names of the files
which need to be updated. e.g. updatehosts hosts.main.  This can be done in
any directory.  Updatehosts knows how to find the files.  The -u option is
used when you want to update the server without modifying any files or you
modified the files by manually running SCCS.