PDP-10.its/doc/syshst/-what-.-file-

XX:<HOSTS>-WHAT-.-FILE-.1,  5-Sep-86 15:21:21, Edit by SRA

This file attempts to document the important files related to MIT host
tables, where the files come from, where they go, etcetera.  No
warranty implied....


Which tables:

	The "MIT host tables" include information for the MIT
	chaosnet and Internet networks 18.0.0.0 and 128.52.0.0.  There
	are also a few overflows from the Arpanet (10.0.0.0) and in
	past days Symbolics and CISL have also been part of the tables
	for various reasons.  The "MIT host tables" are the
	authoritative source of information for the MIT Chaosnet.
	They also contain authoritative information for much of the
	relevant Internet data, but here the organization is not as
	clean; you should also check with the MIT Telecommunications
	Office, who run the MIT.EDU domain and the campus network.
	Contact Jeff Schiller <jis@bitsy.mit.edu> for details.

Directories:

	Host tables primarily live in the SYSHST directory on AI
	(AI:SYSHST;) and in the HOSTS directory on XX (XX:<HOSTS>).
	Other machines will presumably have local copies of these.
	Some of the files also live in XX:<SYSTEM>; these are ones
	that are used directly by XX's system programs.  Similarly,
	the binary HOSTS3 file lives in the SYSBIN directory on all
	ITS machines.


Programs:

Most relevant programs are in XX:<HOSTS>.  I used various languages as
was convient (TECO, Twenex CTL, Twenex PCL, Twenex CMD, C, MIDAS).
You are welcome to read this stuff but probably don't want to touch it
unless you are a Real Hero.


Mailing lists:

The primary list for host table related issues is INFO-HOSTS@AI (aka
AI.AI.MIT.EDU).  There are a couple of spinoff lists.
INFO-HOSTS-UPDATE@AI is a list for people who want to receive SRCCOMs
of changes to HSTMIT from the nightly XX batch job.
INFO-HOSTS-REQUEST is the usual list addition/removal address.
NAMECALLERS@AI is a list to discuss the MIT implementation of the
DARPA Domain system.  You're welcome to listen in but don't speak
unless you know what you are talking about.

Source files:

XX:<HOSTS>HOSTS.NIC:
	This is a copy of the Internet host table maintained by the
	Network Information Center under DARPA contract.  It is the
	closest thing available to a complete listing of the Internet,
	but is somewhat deficient (due to the unmanageable size of the
	table).  The version number of this file tracks the version
	number of [SRI-NIC]NETINFO:HOSTS.TXT.  MIT machines desiring a
	copy of the unadulterated NIC table should copy the one from
	XX rather than getting it directly from the NIC; this was an
	official request from the NIC, to help cut down on the load on
	SRI-NIC due to FTP servers.

	To update this file, send mail to HOSTMASTER@NIC.

AI:SYSHST;HSTNET >
	This file contains about ten lines of machine readable data
	(network names and numbers for MIT nets).  This part is seldom
	changed.  Most of the file is a comment (ignored by the table
	compilers) listing the current subnet assignments for the MIT
	networks.  This is the authoritative listing.  No changes
	should be made to subnet numbers without checking this file to
	see if there is a conflict.  There is a small self appointed
	militia who police this file for reasonableness; talk to the
	people on INFO-HOSTS@AI if you need details.

AI:SYSHST;HSTLCS >
	This is the authoritative host table for LCS.  It is dumped
	from the LCS LispM namespace every time a "significant" change
	is made to the namespace.  Editing the file is a waste of
	time, edit the namespace instead.  Format is a little odd to
	support some additional functionality for the LCS.MIT.EDU
	domain.  A copy of this file lives in XX:<HOSTS>HSTLCS.TXT.
	This file is also the source for the LCS.MIT.EDU domain.

AI:SYSHST;HSTAI >
	This is the authoritative host table for the AI lab.  It is
	dumped from the AI LispM namespace.  Again, edit the namespace
	instead of the file.  File format doesn't have the weird LCS
	kludges.  A copy of this file lives in XX:<HOSTS>HSTAI.TXT.
	This file contains the same data as the AI.MIT.EDU domain.

AI:SYSHST;HSTEE >
	Table for the EECS "domain" (still part of MIT.EDU).  Hand
	edited, but usually pretty up to date.  Is the authoritative
	source for EECS Chaosnet machines.  Internet addresses here
	have to be cleared with Telecommunications, but changes should
	be reflected in this file so that machines which don't grok
	domains yet can keep up with things.  Copy in
	XX:<HOSTS>HSTEE.TXT.

AI:SYSHST;HSTATH >
	Table for the Project Athena "domain" (still part of MIT.EDU).
	Hand edited, may or may not be up to date at a given moment.
	Authoritative source for Athena Chaos machines.  Copy lives in
	XX:<HOSTS>HSTATH.TXT.

AI:SYSHST;HSTG >
	Table for machines not part of LCS, AI, Athena, or EECS.
	Hand edited, may or may not be up to date.  Authoritative for
	Chaosnet.  Copy in XX:<HOSTS>HSTG.TXT.

AI:SYSHST;HSTXXX >
	This is a file of additions and kludges that need to be added
	to the NIC host table (some machines at Stanford and
	Symbolics, other things as needed).  You probably shouldn't
	edit this.

Generated files (produced by XX's nightly host table job):

XX:<HOSTS>HSTMIT.TXT
	Merge of HSTLCS, HSTAI, HSTATH, HSTEE, and HSTG.  This has all
	the special kludges fixed up, names expanded, etcetera.  This
	is the closest thing there is to a single table listing all
	MIT machines.  Copy in AI:SYSHST;HSTMIT >.

XX:<HOSTS>HSTNIC.TXT
	This is derived from the NIC host table.  A few known bad
	names and/or addresses are removed, any nicknames that
	conflict with MIT machines are removed.  Any machines that
	look "insignificant" are removed (workstations at sites other
	than MIT, etcetera).  The contents of this file are subject to
	change without notice as becomes necessary to feed this file
	into some of the later stages of the compilation process.
	HSTXXX is prepended to the NIC data in this file.  No data for
	MIT machines appears in this file; it is implicitly assumed
	that the data in the MIT tables superceedes whatever the NIC
	has on file.

XX:<SYSTEM>HOSTS.TXT
	This is HSTMIT followed by HSTNIC, but without the Chaosnet
	data.  It is as close to a "complete" listing of the DARPA
	Internet as can be made with the current setup.  XX uses this
	file for its old Internet host table software (XX also uses
	the new Domain system, but that's a different issue).
	Machines that want a copy of the NIC table with the MIT data
	fixed should use this file.

XX:<HOSTS>HOSTS3.TXT
	This is a file suitable for feeding to the HOSTS3 binary table
	compiler.  It contains all the essential data from HSTMIT
	followed by HSTNIC.  Some amount of pruning is done to this
	file to fit the address space constraints of the HOSTS3
	compiler (at present, all the services entries are removed).
	Contents subject to change without notice.

XX:<SYSTEM>HOSTS3.BIN
	This is the compiled binary HOSTS3 table.  Many programs on
	ITS and Twenex use this.  Copies can be found in the <SYSTEM>
	directory on all MIT Twenex machines and in the SYSBIN;
	directory on all ITS machines.  Version numbers of the ITS
	copies track that of the XX:<SYSTEM> copy.

XX:<HOSTS>HOSTS2.TXT
	An old format of host table (MIDAS hackers should note the
	syntax!).  Somewhat useless because it can only handle IP
	addresses with the third octet zeroed.  Used to produce...

XX:<SYSTEM>HOSTS2.BIN
	The compiled binary HOSTS2 format file.  Maintained for upward
	compatibility.  No new programs should use this.

XX:<HOSTS>HOST3C.TXT
	A listing of just the Chaosnet machines from HSTMIT.  Name is
	somewhat confusing, since the file format is actually HOSTS2.
	I think the unix binary table compiler reads this file.  Is
	called HOST3C because it is used to produce...

XX:<SYSTEM>HOST3C.BIN
	A HOSTS3 binary format listing of the MIT Chaosnet.

XX:<HOSTS>MITGWS.TXT
	A listing of (IP) gateways and (Chaos) bridges, produced from
	HSTMIT.  No warranty, but very handy for tracking down
	network problems, since it is usually more up to date than any
	of the gateway maps available.  Copy in AI:SYSHST;MITGWS >.

XX:<HOSTS>CHAOSHOSTS.CHAOS-ALL
	A file in the format used by unix sendmail, usually installed
	as /etc/chaoshosts.  This file contains a listing of all
	chaosnet hosts at MIT (derived from HSTMIT).

XX:<HOSTS>CHAOSHOSTS.CHAOS-ONLY
	Same as CHAOSHOSTS.CHAOS-ALL but only lists hosts that are on
	the chaosnet but aren't on the Internet.  Depending on whether
	your vax is or isn't on the net you will want one or the other
	of these files so that sendmail can route mail as efficiently
	as possible.

There are some other files associated with the LCS.MIT.EDU domain, but
that's a whole separate topic and not relevant here.