I see that the draft has consolidated all the previous drafts that
highlighted the issues
of NAT-PT and DNS ALG, which is a good thing. However, most of the
issues mentioned
here as NAT-PT issues are known issues with address translation (NAT)
itself, so
attributing them to NAT-PT is not correct. Those should be categorized
as generic address
translation issues.
Some specfic comments on the following issues.
* Disruption of all protocols which embed IP addresses (and/or
ports) in packet payloads or which apply integrity mechanisms
using IP addresses (and ports). (not NAT-PT specific).
* Requirement for applications to use keep alive mechanisms to
workaround connectivity issues caused by premature NAT-PT state
timeout. (not NAT-PT specific).
* Inability to redirect packet fragments after the first with
NAPT-PT. (not NAT-PT specific).
o Issues which are exacerbated by the use of a DNS-ALG:
* Constraints on network topology. (not NAT-PT specific).
* Scalability concerns together with introduction of single point
of failure and security attack nexus.(not NAT-PT specific).
* Lack of address mapping persistence: Some applications require
address retention between sessions. The user traffic will be
disrupted if a different mapping is used. The use of the
DNS-ALG to create address mappings with limited lifetimes means
that applications must start using the address shortly after
the mapping is created, as well as keeping it alive once they
start using it.(not NAT-PT specific).
* Creation of a DOS threat relating to exhaustion of memory and
address/port pool resources on the translator.(not NAT-PT
specific).
Regarding the conclusion, I don't agree with the fact that only
applicable scenario
is in 3G networks. During the past couple of years of my experience I
have seen
customers using it between isolated IPv6 networks to talk to existing
IPv4 networks.
A lot of cases it is not about the nodes being dual stack or not, it is
the network
that is not dual stacked for operational reasons.
I have been gathering some inputs from the customers who are using
NAT-PT currently
regarding this draft. I can consolidate and forward the comments if you
are interested in
knowing and understanding why they think they are moving forward with
NAT-PT.
The point I am trying to stress is deprecating this would leave us with
no workable
solution for communicating between IPv4 only networks/nodes/apps IPv6 only
networks/nodes/apps. As remote as it might seem for some, that is the
use case
scenario we have encountered as the applicability of NAT-PT.
Senthil
At 10:12 AM 9/22/2004 +0200, Cedric Aoun wrote:
Hi,
As discussed at IETF 60, the WG agreed to continue the NAT-PT
deprecation analysis.
We would really appreciate if you could provide us your feedback on
the initial version of the deprecation analysis by Monday October 4th.
Regards
Cedric Aoun
------ Forwarded Message
From: <Internet-Drafts@ietf.org>
Reply-To: <internet-drafts@ietf.org>
Date: Tue, 21 Sep 2004 21:38:33 +0200
To: <i-d-announce@ietf.org>
Subject: I-D ACTION:draft-aoun-v6ops-natpt-deprecate-00.txt
A New Internet-Draft is available from the on-line Internet-Drafts
directories.
Title : Reasons to Deprecate NAT-PT
Author(s) : C. Aoun, E. Davies
Filename : draft-aoun-v6ops-natpt-deprecate-00.txt
Pages : 24
Date : 2004-9-21
This document discusses reasons why use of the specific form of
IPv6-IPv4 protocol translation mechanism implemented by the Network
Address Translator - Protocol Translator (NAT-PT) defined in RFC 2766
should be deprecated and RFC2766 moved to historic status.
Description of an alternative protocol translation mechanism is out
of scope for this document.
A URL for this Internet-Draft is:
<http://www.ietf.org/internet-drafts/draft-aoun-v6ops-natpt-deprecate-00.txt>http://www.ietf.org/internet-drafts/draft-aoun-v6ops-natpt-deprecate-00.txt
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