Unusual use of IP Broadcast Address

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Date: Wed, 12 Jan 1994 10:47:28 -0500
From: [e-mail] (Wendy Etkind)
To: [e-mail]
Subject: rfc1020

Mr. Postel:

In rfc1020 the internet address 255.255.255.255, the broadcast
address, is reserved for you. Granted this is a special address,
would it be illegal for me to route the broadcast address to a
specific network?

For example, for purposes of my network protocol development I have
reserved the subnets 129.83.14 and 129.83.15 for my personal use.
These subnets are within the MITRE beford domain (MITRE bedford
has all of 129.83).

I am developing a network protocol for the government (a tactical
protocol called TACO2 which is based heavily on MIT's netblt and
includes standard IP, slip and a subset of hdlc). I have this
protocol (TACO2) running on both Suns and pcs. I have ttya set to
129.83.14 and ttyb set to 129.83.15. I would like to transmit to a
pc which is attached to my tty port. The tty to pc connection is
the tactical connection. Usually there are satellites or HF radios
in between the tty port and the pc. 

Since I will not always know the address of the pc I would like to
address it as 255.255.255.255. Of course I would like the pc
attached to ttya to be on the 129.83.14 subnet but this may not
be possible. These pcs will never be on the internet so people have
been using their own addresses.

I have a modified version of "route" which will route the broadcast
address to my 129.83.14 gateway (the tty port). Using this private
route I can transmit to the broadcast address and the resulting
packets go out the tty port rather than to all address (and does
not go out the ethernet).

Before I release this version of route and let my users send to the
broadcast address I want to make sure that this is legal as far
as standard internet numbering schemes are concerned. While my pcs
will never be on the internet, I expect at some point, that the Sun
will act as a tactical to stragic gateway. The Sun could be on the
internet (or the milnet perhaps) and the Sun's tty ports would
be attached to the tactical pcs. I will use tcp/ip for normal
(ethernet) internet traffic and TACO2 for the tactical (tty) traffic.
If I have the Sun on the internet then I want to make sure that I am
doing legal things with respect to the broadcast address, especially
if I am considering redirecting it.

		Thank you for your time,

		Wendy Etkind

Wendy Etkind ([e-mail] or linus!mbunix!etkind)
Member of the Technical Staff: Imaging Systems, Mitre Corp.



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