Subject: Re: IP network address assignments/allocations information?

From: "Tony Dal Santo" <[email-masked]>
Date: Tue, 30 Nov 1999 11:28:50 -0500

Valdis Kletnieks wrote:

> However, I do agree that anybody designing a protocol in the last 3-4
> years *should* have designed it to be firewall and NAT friendly.
> (Yes, I know that can be difficult in practice.  I guess that's today's
> "Welcome to Reality").

Daniel Senie wrote:

> > In any event, I've always personally been of the opinion that
> > if applications don't work in the face of NAT, then the
> > applications themselves are functionally deficient and should be
> > fixed.  :-)
>
> ...and [NAT] must be taken into consideration when designing protocols.
>
>    ....        New protocols should, in my opinion, provide descriptions
> of how they work or don't work with NAT. If there is a reason why they
> aren't going to work (carriage of port or address information), a
> description of how to build an Application Layer Gateway (ALG) should be
> provided.

I really think trying to make everything "NAT aware" or "NAT friendly"
is spending effort heading in the wrong direction.  While I am forced to
concede the wide deployment of NAT technology, I believe the problems it
solves (or at least claims to) are better solved by other means, or
require different solutions.

Protocols are difficult enough to get right.  I'd rather see time spent
developing good algorithms than NAT compatibility.  What about future
NAT "features"?  Are protocol designers supposed to guess at what new
convolutions will be dreamt up?

About the only serious issues NAT really addresses are the perceived IP
address shortage, and being forced to renumber when changing ISPs.  As
for the shortage, this thread seems to indicate there isn't a real firm
idea of how many addresses are actually being used.  Have all the minimally
used class A and B addresses been reclaimed?  I suspect not, which tells
me the immediate shortage can't be that great.  And if switching to IPv6
in the long term has problems, effort should be spent solving those.

As for being forced to renumber (can't take your address with you),
is this really a technical routing problem (tables too large), or more
of an economic/political/turf issue?  While renumbering can be painful,
DNS should hide the change, and things like DHCP can make it less so.
Besides it shouldn't be too difficult for small organizations, and large
ones should be able to take their address as they move.

While NAT is an adequate stopgap solution to IP address dilemmas, in my
opinion, it shouldn't be the final solution.

> We are at a crossroads where architectural purity has intersected
> operational reality.

Let's not continue down the wrong road.

Tony

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From: John Day <[email-masked]>
Date: Tue, 30 Nov 1999 17:17:21 -0500

>require different solutions.

The problem is not to make applications "NAT aware" or "NAT friendly".  The
problem is to make applications "IP address unaware".  What is an
application doing exchanging and using names for things 2 layers below it?
Sounds like a design for trouble if I ever heard of one.
>convolutions will be dreamt up?

You are absolutely right.  Time should be spent developing "good
algorithms" which is common "good architecture".  What NAT does is just
another form of the same thing that X.25, ATM, and MPLS do with different
identifiers.  It is not bad algorithm there nor bad architecture.  (I
presume since there are so many ATM and MPLS supporters (X.25 seems to be
gone for the most part, thank god.))  How does an application exchanging
and using IP addresses qualify as good algorithms or good architecture.
>As for being forced to renumber (can't take your address with you),

No, you can't.  If you did it would no longer be an address, but only a
name. And then of no use to routing.

>is this really a technical routing problem (tables too large), or more

It is really a technical problem.

>of an economic/political/turf issue?  While renumbering can be painful,

Only trying to keep the address is an economic/political/turf issue.

>ones should be able to take their address as they move.

Now you are on to the beginning of a good solution.
>Let's not continue down the wrong road.

Correct.  Lets get an application name space so we don't need to worry
about it.

Take care,
John

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From: John Day <[email-masked]>
Date: Tue, 30 Nov 1999 17:17:21 -0500

Take care,
John

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From: Mark Atwood <[email-masked]>
Date: 30 Nov 1999 15:12:46 -0800

> Correct.  Lets get an application name space so we don't need to worry

Please gods below, not more ASN.1

-- 
Mark Atwood               | 
[email-masked]             | 
http://www.pobox.com/~mra |

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From: Mark Atwood <[email-masked]>
Date: 30 Nov 1999 15:12:46 -0800

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From: John Day <[email-masked]>
Date: Tue, 30 Nov 1999 22:52:33 -0500

>Please gods below, not more ASN.1

What a strange reaction!?  What does an arcane syntax notation have to do
with Shoch's observation that there are 3 kinds of addresses:
applications, hosts, and routes?  What have you been smoking?

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From: John Day <[email-masked]>
Date: Tue, 30 Nov 1999 22:52:33 -0500