Subject: Re: dialup PPP (material for interim meeting)

From: Jari Arkko <[email-masked]>
Date: Mon, 04 Jun 2001 18:04:31 +0300

Thanks for the interesting draft. (Was this discussed
at the interim and were there any notes taken?)

One issue should perhaps also be taken up in the context
of IPv6 and PPP. As we are moving (gprs etc) towards a
more always-on world, it is possible that I run a PPP link,
for instance, between my PDA and a GPRS terminal basically
as a permanent connection. Do I want to retain the same
address on it all the time, or should I be able to run
the privacy extension (RFC 3041) over PPP as well? I.e.
even in the static addressing model that you mention there
may be needs to change the address for privacy reasons.

Jari
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From: Jun-ichiro itojun Hagino <[email-masked]>
Date: Tue, 05 Jun 2001 00:12:32 +0900

>at the interim and were there any notes taken?)

	i hope that there's a note, there was a highly active discussions
	(partly because the draft kept many options open).

>may be needs to change the address for privacy reasons.

	basically the above highly depends on the assuption you make for
	address assignments to PDA/GPRS devices.
	if you follow "allocate /64 to the network behind the device" model
	(2nd bullet in section 2.4), you can generate new source address out
	of the given /64 at will.

itojun

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From: Michael Thomas <[email-masked]>
Date: Mon, 4 Jun 2001 08:38:52 -0700 (PDT)

> 	of the given /64 at will.

  Er, that doesn't strike me as especially private. If there's
  a named device at that /64, I can pretty much use that subnet
  prefix to triangulate who the manufactured address is. I assume
  that many/most widgets will be named since they want to recieve
  INVITE's, and other peer-peer services.

	    Mike

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From: [email-masked]
Date: Tue, 05 Jun 2001 00:42:50 +0900

>  INVITE's, and other peer-peer services.

	if you want to accept inbound connections, i guess it is highly
	difficult to keep privacy anyways.  what is your definition of
	"privacy" here?  traffic analysis is inherently a hard problem.
	RFC3041 only solves (possible) issue (for those who cares) with
	EUI64-derived interface identifier, not others.

itojun

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From: Michael Thomas <[email-masked]>
Date: Mon, 4 Jun 2001 08:49:31 -0700 (PDT)

> 	EUI64-derived interface identifier, not others.

  You're probably right. I guess I find the whole concept
  of address privacy as it's constituted in RFC3041 to be
  pretty, well, underwhelming on the privacy front. If you
  want privacy, use an application layer anonymizer.

		Mike