Re: GSE IDs [Re: IETF multihoming powder: just add IPv6 and stir]

[marcelo bagnulo <marcelo@it.uc3m.es>]

On Thu, 2003-05-08 at 13:30, Iljitsch van Beijnum wrote:
> On donderdag, mei 8, 2003, at 13:10 Europe/Amsterdam, marcelo bagnulo 
> wrote:
> 
> > I guess that what Brian means is that this (what you are describing) is
> > not GSE anymore, since it is not stateless (which is a fundamental
> > feature of GSE, as i see it)
> 
> No disagreement there.
> 
> > what you are describing sounds more like MHAP...
> 
> Originally, I wanted to write something that encompasses both MHAP and 
> GSE. But:
> 
>    "The original GSE and 8+8 drafts split the IPv6 address in two 64-bit
>     parts. The lower part is used within the site or subnet. Routers add
>     the higher 64 bits as packets leave the site. Since hosts don't know
>     the higher 64 bits their correspondent will see, they must disregard
>     these bits, which has the relatively minor consequence that the TCP
>     and UDP pseudo header used in checksum calculations must be changed.
>     A more severe consequence is that the lower 64 bits must now be
>     globally unique. This in turn makes it very easy to perform spoofing
>     attacks, as an attacker can simply present arbitrary lower bits,
>     thereby assuming any desired identity, while setting the higher bits
>     such that the packets are routed back to the attacker and not to the
>     host identified by the lower 64 bits. This vulnerability, breaking
>     autoconfiguration and, to a lesser degree, the transport layer
>     checksums, make adopting GSE or 8+8 unfeasible and undesirable."
> 
> Is there anyone who disagrees and feels stateless GSE is still viable?
> 

I think that the statless condition of GSE is really valuable and
perhaps we can come up with a solution that can preserve it. 

As you mention, security issues need to be solved somehow in order to
enable this solution.

A possibility would be to use crypto identifiers such as in HIP but
included in the 64 lower bits of the address (CGAs)

I guess that this could provide the security needed and it would also
preserve middle boxes stateless as in GSE.


Regards, marcelo
 

> The letter combination "GSE" will not appear in the title. The 
> preliminary title is "Multihoming in IPv6 by Rewriting Addresses".
-- 
marcelo bagnulo <marcelo@it.uc3m.es>
uc3m