Subject: (ngtrans) Comments on draft-hallin-natpt-dns-alg-solutions-00.txt

From: [email-masked]
Date: Sun, 14 Jul 2002 04:27:27 +0100

Hi Per,

Some comments on your draft below - also see my recent mail to Alain Durand
regarding his original dns-alg-issues draft:

1. Introduction

 ...

   IETF has recognized some
   problems with the DNS-ALG described in [NAT-PT].

=> That's a little strong isn't it? All we have at the moment is a personal
I-D.

2.1 AAAA answers for A queries

 ...

   NAT-PT should only be used by IPv6-only nodes.  These nodes should
   not use IPv4 DNS (A), thus the NAT-PT should refuse any A queries
   made by internal nodes.

=> As has been pointed out by others, this is the wrong solution. The
DNS-ALG must relay or translate queries as appropriate.

2.2 Source Address Selection/Destination ordering

=>  If a clear separation is made between "relaying" and "translating" DNS
transactions then this problem will not arise; any A records within a
relayed AAAA response would not be translated, and so the only IPv6
addresses in the response would be genuine ones.

2.3 NAT-PT & IPv6 default router

 ...

   It is not necessary for the NAT-PT to be the only default router
   in the IPv6 domain.  The only traffic that has to go through the NAT-
   PT is the one that needs to be translated.

=> Yes, and an alternative way to achieve this is for all hosts to use a
local IPv6 DNS server which is configured to forward unknown queries to
NAT-PT-PREFIX::IPv4-DNS.

 -- Mat.