Subject: Numbers of NAT-s in IPv4/IPv6 Network? One or more?

From: Bilajbegovic Damir <[email-masked]>
Date: Fri, 12 Sep 2003 10:11:58 +0200

Case: local network connected to the public IP network

If I understood right, in normally network translation (local IPv4 to public
IPv4), there must be only one NAT (simplest solution) at the border of
network. (NAT-PT and all necessarily ALG)

If there is translation between IPv4 intranet and IPv6 public network can
then be more than NAT-PT? (all intranet is IPv4, and all public is IPv6)

If you know the answer or you can direct me to some document I would be
grateful.
         Damir Bilajbegovic

P.S: In translation IPv4/IPv6 there is always translation, and nor IPv4
user, nor IPv6 server do not see directly each other, they see IPv4 address
which NAT gives to server, and IPv6 server sees IPv6 address of user by
which NAT represents user. Every packet will go directly to specific NAT
(the one who knows translation parameters of connection). So, I do not see
any problem in translation. I'm I wrong.

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From: Fred Templin <[email-masked]>
Date: Mon, 15 Sep 2003 11:33:02 -0700

This is an interesting question, and I'm certainly no expert on
the subject. But, in theory, couldn't there be more than one NAT
if, e.g., the (multiple) NAT boxes communicated out-of-band
to keep a consistent view of the aggregate state information?
(Then, you get into questions as to whether the multiple NATs
are there for something simple like load balancing/fault tolerance,
or for something more complex like site multi-homing.)

I guess I don't have anything conclusive for you on this, but just
to note that the "must" in your statement: "there must be only
one NAT" may be a bit too strong.

Fred
[email-masked]

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From: Gert Doering <[email-masked]>
Date: Mon, 15 Sep 2003 21:34:33 +0200

Hi,

> to keep a consistent view of the aggregate state information?

It is possible, and it's actually being done in practice.  Some
firewall boxes can do this in a high-availability active/active
configuration (for example).

> or for something more complex like site multi-homing.)

marketed as load balancing / fault tolerance.

Besides the case of multiple NATs working "parallel", I have also seen
cases where multiple NATs where daisy-chained (wireless network being
NATted to the fixed in-house network, which in turn was NATted to one
outside IP).  Ugly, but real.

Gert Doering
        -- NetMaster
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SpaceNet AG                 Mail: [email-masked]
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From: Pyda Srisuresh <[email-masked]>
Date: Mon, 15 Sep 2003 17:04:58 -0700 (PDT)

Please see my comments in-line.

cheers,
suresh

> or for something more complex like site multi-homing.)
You might want to take a look at draft-park-scalable-multi-natpt--00.txt that
proposes to do precisely that.

> one NAT" may be a bit too strong.

I think so, as well.

> >any problem in translation. I'm I wrong.

=====

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From: Soohong Daniel Park <[email-masked]>
Date: Tue, 16 Sep 2003 11:29:53 +0900

sorry for being late in responding to this subject...
please refer to the below easy link.

> You might want to take a look at
> draft-park-scalable-multi-natpt--00.txt that

http://www.ietf.org/internet-drafts/draft-park-scalable-multi-natpt-00.t
xt

Daniel (Soohong Daniel Park)
Mobile Platform Laboratory, SAMSUNG Electronics