Subject: Re: illegal network routes and a ponderance
To: None <firstname.lastname@example.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
Date: 02/19/2003 09:39:44
>>> Why is this (having a route pointing to a gateway that's not on net
>>> for any interface) not supported,
>> My guess is, because it does not match IP's routing model,
> Well, it seems to match the routing model of source routing, but I
> would like to know for sure, as I'm not very familiar with source
Hmm. Yes, if what it does is construct an LSRR (or perhaps even SSRR)
option on outgoing packets, and is ultimately grounded in a
directly-reachable host, I believe you're right.
My apologies. I was (mis)reading your suggestion as being a slight
variant of the original one, which it's not.
>> But quite aside from what it does to the assumptions underlying IP,
> What does it do to the assumptions underlying IP concretely?
That every host that can send a datagram into a network has an address
in that network. (This is why your suggestion, constructing a
source-route option, isn't actually a problem, because it doesn't
involve hosts sending into networks to which they have an interface
physically connected but in which they do not appear in IP terms.)
>> how would you cut off infinite loops?
> Isn't the Source Routing option (for IPv4) limited in size? There
> would be no point in having more loops than this limit.
True, and that limit _is_ relatively small. Okay, I'm answered.
/~\ The ASCII der Mouse
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