Subject: (ngtrans) RE: NAT-PT

From: [email-masked]
Date: Wed, 16 Feb 2000 10:44:05 -0000

> -----Original Message-----
> From:	Kornel Szegedi [SMTP:[email-masked]]
> Sent:	Wednesday, February 16, 2000 9:59 AM
> To:	ngtrans; [email-masked]; [email-masked]
> Subject:	NAT-PT
> 
>         Hi,
> 
>  I have a question about NAT.
>  In rfc2766, chapter 3.1 "Basic-NAT-PT Operation" a technique is
> introduced which does not use  DNS-ALG. The following example can be
> found here:
> 
> | Say the IPv6 Node A wants to communicate with the IPv4 Node C.  Node A
> creates a packet with:
> |
> |       Source Address, SA=FEDC:BA98::7654:3210 and
> |       Destination Address, DA = PREFIX::132.146.243.30
>         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> My question is: how can Node A acquire the address of Node C? Node A
> sends an "AAAA" query to the local DNS server. Suppose it does not know
> the address of Node C, so it forwards the query to the next level DNS
> server. The query passes through the NAT-PT (if we assume that the
> server is located outside the NAT-PT) but since no DNS-ALG is present
> there it is not translated to a type "A" query,  and no address will be
> returned by the DNS server.
> 
>     Is my understanding right or is there something I did't take into
> account?
> 
> 
	Kornel,

	NAT-PT requires the existence of DNS-ALG so its OK.
	If you *do not* want to use DNS-ALG you may be able to use the SIIT
mechanism in combination with NAT-PT. SIIT recognises IPv4 addresses as IPv4
mapped IPv6 addresses in which case the PREFIX in the example above is
always 0::0/96. 

	Hope this helps
	George

>                         Kornel