Re: [v6ops] RFC6459 "IPv6 in 3GPP" - the IID in the LL address

[Gert Doering <[e-mail]>]

Hi,

On Mon, Jul 10, 2017 at 07:53:52PM +0200, Alexandre Petrescu wrote:
> > [..]
> >> Some packets with LLs as src have been witnessed in the Internet at large.
> > 
> > This is a bug in all the forwarding entities on the path and needs to be
> > fixed.
> 
> That is your oppinion.

It's clear violation of internet standards that say "such packets MUST NOT
be forwarded", so what else can it be but "a bug"?

> There should be nothing wrong in sending packets to the Internet. 
> Forwarding is based on the dst address.

Please do less thinking, and more reading of standards.

We've been here before.

[..]
> >> Some times some UE apps may put a link-local address in
> >> application-layer payloads.  Some protocols do it too (e.g. OSPF puts
> >> LLs in LSAs, DHCP puts interface IDs and LLs in payloads, etc).
> > 
> > This would be a bug in the application, which would need to be fixed.
> 
> Well - I think you dont understand.

Yeah.

> Speaking only for DHCP here:
> 
> DHCP carries interface IDs in UDP payloads.  They're called "Link-layer 
> address" 48bit, in Client Identifier, as an UDP payload in DHCPv6 
> Solicit, by the User Terminal.

That is not a protocol commonly routed across the internet, so it is of
total irrelevance in this context (and, using MAC address as client 
identifier is strictly optional in DHCPv6, unlike IPv4)

> If the Server is in the operator's network, then one could think that 
> there is no more tracking danger than without DHCP.  But if the Server 
> and intermediary routers are outside the operator's network then there's 
> real risk of tracking.

How many networks do you know that route DHCPv6 requests about arbitrary
third party infrastructure?

> One could not fix the DHCP protocol to eliminate that Client identifier, 
> because if so then DHCP will no longer work.

Less thinking, more reading.  DHCPv6 initially was specified based on
DUIDs, and *not* MAC addresses.

Gert Doering
        -- NetMaster
-- 
have you enabled IPv6 on something today...?

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