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Date: Wed, 28 Jun 1995 14:39:20 -0400
From: Garrett Wollman <wollman@halloran-eldar.lcs.mit.edu>
Message-Id: <9506281839.AA01339@halloran-eldar.lcs.mit.edu>
To: nate@sneezy.sri.com (Nate Williams)
Cc: Garrett Wollman <wollman@halloran-eldar.lcs.mit.edu>,
        "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com>,
        jkh@freebsd.org (Jordan K. Hubbard),
        FreeBSD-current@freebsd.org (FreeBSD current)
Subject: Re: Paul Richards: sysconfig routed setting
In-Reply-To: <199506281837.MAA03494@rocky.sri.MT.net>
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<<On Wed, 28 Jun 1995 12:37:45 -0600, nate@sneezy.sri.com (Nate Williams) said:

>> If you are not a router, you have no business
>> listening to them.  HOSTS DO NOT NEED ROUTING INFORMATION.

> OK, given your assertion's, HOW is machine B supposed to send data to
> my machine?

       
> Ethernet =
> SLIP/PPP *

>               machine-A<=>machine-B<=>machine-C<*>{internet}
>                   ^
>                   *
>                   v
>              Nate's box


Machine A is a router.  It runs a routing protocol.

> With your assumption, machine B does is not running any routing
> software, so therefore it does not know to send packets to machine A in
> order to get to my machine.

Machine B has a default router R.  R and A exchange routing protocol
packets to inform each other of their locations.  When machine B sends
a packet for `Nate's box' to R, R sends an ICMP redirect back to B
telling it that `Nate's box' should be reached by way of A, and B
sends future packets directly.

-GAWollman

--
Garrett A. Wollman   | Shashish is simple, it's discreet, it's brief. ... 
wollman@lcs.mit.edu  | Shashish is the bonding of hearts in spite of distance.
Opinions not those of| It is a bond more powerful than absence.  We like people
MIT, LCS, ANA, or NSA| who like Shashish.  - Claude McKenzie + Florent Vollant