Subject: (ngtrans) Re: comments on draft-itojun-v6ops-v4mapped-harmful-00.txt

From: Jun-ichiro itojun Hagino <[email-masked]>
Date: Wed, 18 Sep 2002 00:26:46 +0900

(since this is transition tool discussion replies to ngtrans please)

>The assumptions behind SIIT is that the node is dual stack (the protocols
>as well as the applications) but the node  doesn't have a permanent IPv4
>address and the local network infrastructure does not support IPv4.
>With those assumptions there aren't any strange requirements on the devices
>(ignoring the AH suggestion in the RFC:-); the ftp implementation on a 
>dual stack node already needs to support old stuff when communicating with
>IPv4 addresses.

	if the above assumption is true, what do you intend to do about the
	dual use of IPv4 mapped address?  telnet client on dual stack machine
	would make a send(2) request to ::ffff:a.b.c.d, which will be captured
	by an AF_INET6 socket, and goes out of the node as IPv4 packet.
	there's no documented way in which ::ffff:a.b.c.d would go out as IPv6
	packet.  either RFC2553 API does not work, or SIIT dose not work.

itojun

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From: Vladislav Yasevich <[email-masked]>
Date: Tue, 17 Sep 2002 13:42:38 -0400

Itojun

> 	packet.  either RFC2553 API does not work, or SIIT dose not work.

This packet will only go out as an IPv4 packet if there was an IPv4 address
available.  If the node implements SIIT and there is not IPv4 address, the
packet will go out as a SIIT formatted IPv6 packet (i.e with a translatable 
source.

A node that does not implement SIIT that happens to receive a SIIT formatted
packet will simply drop the packet because ::ffff:a.b.c.d IPv6 address is
not configured on any IPv6 interfaces of the node.

-vlad

-- 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Vladislav Yasevich	       Tru64 UNIX - IPv6 Project Lead
Hewlett Packard 	       Tel: (603) 884-1079
Nashua, NH 03062	       ZKO3-3/T07

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From: Jun-ichiro itojun Hagino <[email-masked]>
Date: Wed, 18 Sep 2002 02:56:33 +0900

>not configured on any IPv6 interfaces of the node.

	i have never seen such sender rule written down anywhere, and such rule
	complicates sender's behavior.  do you have any reference?

itojun

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From: Erik Nordmark <[email-masked]>
Date: Fri, 20 Sep 2002 11:11:27 +0200 (CEST)

> 	(since this is transition tool discussion replies to ngtrans please)

I thought the topic of the discussion was draft-itojun-v6ops
which the author seems to think belongs in v6ops :-)

> 	packet.  either RFC2553 API does not work, or SIIT dose not work.

An implementation needs to be configured to either be IPv6-only or
dual stack.
In the dual stack case the mapped addresses at the API correspond
to IPv4 packets on the wire.
In the IPv6-only case the mapped addresses at the API correspond
to IPv6 packets on the wire next to the node, and on the other side of
the translator they correspond to IPv4 packets.

What part of section 3.7 in RFC 2553 conflicts with this?
That section doesn't say that IPv4 packets are sent, it says that the
address is used to for IPv6 applications to interoperate with IPv4
applications. 

What part of the SIIT spec conflicts with RFC 2553?

Please be specific.

  Erik