Re: [Fwd: I-D Action: draft-carpenter-6man-why64-00.txt]

Hello,

(first message on these lists, hope it is accurate)

I'm generally thinking that the /64 limit helps to structure the address space from the receiver point of view. Let's say i'm running a mail server which tries to reduce spam by temporarily blacklisting some senders. if i'm facing spammers who use their IPv6 address space in a smart way, they will just have to generate RFC 4941 addresses to exhaust a firewall memory. The pragmatic way to face such attacks is to blacklist the whole /64, never a unique /128.

I don't know if it is to be considered as a best practice, but for these reasons, as a receiver, i personally consider a /64 to be assigned to a unique link, or at least a network managed by a unique network administrator. Enforcing this limit in protocol standards strengthen this assumption. This might be an additional argument for the "please keep /64 for unique links".

As a consequence, subdivide a /64 into several prefixes in order to assign it on several networks might create a risk for devices on one network to be blacklisted by actions performed by some devices on another network, in case the whole /64 have been blacklist by a "pragmatic" receiver. 

Best regards
Emmanuel Thierry

Le 5 janv. 2014 à 23:07, Brian E Carpenter a écrit :

> Hi,
> 
> A group of us put this together following a discussion some weeks
> ago on the v6ops list about the 64-bit boundary in IPv6 addresses.
> Discussion belongs in 6man, please.
> 
> This draft is incomplete but we'd welcome input. Let me underline
> an important comment in the introduction:
> 
>  _The purpose of this document is to analyse the issues around this
>   question.  We make no proposal for change, but we do analyse the
>   possible effects of a change._
> 
> 
>   Brian + co-authors
> 
> -------- Original Message --------
> Subject: I-D Action: draft-carpenter-6man-why64-00.txt
> Date: Sun, 05 Jan 2014 13:59:17 -0800
> From: internet-drafts@ietf.org
> Reply-To: internet-drafts@ietf.org
> To: i-d-announce@ietf.org
> 
> 
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> 
> 
>        Title           : Analysis of the 64-bit Boundary in IPv6 Addressing
>        Authors         : Brian Carpenter
>                          Tim Chown
>                          Fernando Gont
>                          Sheng Jiang
>                          Alexandru Petrescu
>                          Andrew Yourtchenko
> 	Filename        : draft-carpenter-6man-why64-00.txt
> 	Pages           : 14
> 	Date            : 2014-01-05
> 
> Abstract:
>   The IPv6 unicast addressing format includes a separation between the
>   prefix used to route packets to a subnet and the interface identifier
>   used to specify a given interface connected to that subnet.
>   Historically the interface identifier has been defined as 64 bits
>   long, leaving 64 bits for the prefix.  This document discusses the
>   reasons for this fixed boundary and the issues involved in treating
>   it as a variable boundary.
> 
> 
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-carpenter-6man-why64/
> 
> There's also a htmlized version available at:
> http://tools.ietf.org/html/draft-carpenter-6man-why64-00
> 
> 
> 
> 
> 
> 
> 
> 
> 
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