https://news.ycombinator.com/item?id=18376916

I dug up an "explosive bolts" reference -- fortunately that brilliant plan didn't get far.

Milo Medin knows this stuff first hand:

https://web.archive.org/web/20180505024303/https://innovatio...

To: fair@ucbarpa.berkeley.edu (Erik E. Fair)
Cc: ucdavis!ccohesh@ucbvax.berkeley.edu, Hackers_Guild@ucbvax.berkeley.edu
Subject: Re: a question of definition
Date: Thu, 29 Jan 87 12:29:36 PST
From: Milo S. Medin (NASA ARC Code ED) <medin@orion.arpa>

Actually its:

SCINET -- Secret Compartmented Information Net (if you don't know what
compartmented means, you don't need to ask)
DODIIS -- DoD Intelligence Information Net

The other stuff I think is right, at least without me looking things
up. I probably shouldn't have brought this subject of the secure part
of the DDN up. People like being low key about such things...

Erik, all the BBN gateways on MILNET and ARPANET currently comprise
the core, not just mailbridges. Some are used as site gateways, others
as EGP neighbors, etc... And just because you are dual homed doesn't mean
you get a mailbridge. And the IETF doesn't deal with low level stuff
like that; DCA does all that. In fact, the reason we are getting an
ARPANET PSN is because when DCA came out to do a site survey, they
liked our site so much they asked if they could put one here! It's
amazing how many sites have tried to get ARPANET PSN's the right
way and have had to wait much longer than us... BTW, since we are
dual homed (probably a gateway with 2 1822 interfaces in it), we
are taking steps to be sure that people on ARPANET or MILNET can't
use our gateway to bypass the mailbridges. The code will be hacked
to drop all packets that aren't going to a locally reachable network.
BARRNet, even though its locally reachable, will be excluded
from this however, since the current procedural limitations call for
not allowing any BARRNet traffic to flow out of BARRNet to MILNET
and the reverse. NASA traffic of course can traffic through BARRNet,
and even use ARPANET that way (though that's not a big deal when
we get our own ARPANET PSN). That's because only NASA is authorized
to directly connect to MILNET, not UCB or Stanford, etc...

DCA must have the ability to partition the ARPANET and MILNET in
case of an "emergency", and having non-DCA controlled paths between
the nets prevents that. There was talk some time ago about putting
explosive bolts in the mailbridges that would be triggered by
destruct packets... That idea didn't get far though...

The DDN only includes MILNET,ARPANET,SCINET,etc... Not the attached
networks. If it did, you'd need to file a TSR to add a PC to your
local cable. A TSR is a monstrous piece of paperwork that needs to
be done anytime anything is changed on the DDN... Rick knows all
about them don't you Rick?

The whole network game is filled with acronyms! I gave up trying
to write documents with full explainations in terms long ago...
I have yet to see a short and concise (and correct) way of describing
DDN X.25 Standard Service for example... That's probably one of the
harder things about getting into networking these days. We won't
even talk about Etherbunnies and Martians and other Millspeak...

Milo '1822' Medin