Re: [homenet] IPv6 & firewall config in a home net

[Ray Hunter (v6ops)]

Mikael Abrahamsson wrote on 06/09/2019 08:59:

On Thu, 5 Sep 2019, Ray Hunter (v6ops) wrote:

IMHO Expected behavior. Many European data protection people consider 
an IP(v6) address to be privacy-sensitive personal data. That will 
likely mean regular renumbering of IA PD by ISP's as the norm rather 
than the exception.


This is the first time I've seen anyone make this claim (I guess 
related to GDPR). I've gone through GDPR review and talked to others 
who have done the same, and I from a GDPR point of view there is no 
reason to renumber on a regular basis. From what I can tell, 
renumbering at some frequency makes no difference from a GDPR point of 
view. The addresses are privacy sensitive regardless if you change 
them frequently or not.

This last sentence is key.

FYI The opinion I read was as follows:

"The same also applies to IP addresses. If the controller has the legal 
option to oblige the provider to hand over additional information which 
enable him to identify the user behind the IP address, this is also 
personal data."


So if the provider intentionally destroys any method of linking an IP 
address to a user behind an address (by regularly renumbering using 
pseudo-random prefixes) then by the opposite argument the IP address 
shouldn't be considered personal data any more.


This is a method that I've also seen used to pseudo-anonymize MAC 
addresses logged via wifi in a building management system. The MAC 
addresses were hashed with a pseudo random key that rotated every day, 
and the key was not stored anywhere. So the location data could be 
tracked accurately for an individual device over a period of 24 hours, 
but the privacy people considered this good enough that the result 
wasn't considered as personal data, because there was no practical way 
to work backwards from the hashed addressed to the movements of an 
individual device carried by an individual person.


I ain't a lawyer.


My experience is that the frequent renumbering is a local market 
practice that people in that market got used to. As a swedish user, I 
hadn't heard of this practice until I started talking about these 
things with people that ran/experienced ISPs in other nations. The 
defaults are also different.


Some markets have frequent renumbering (some even reset the PPPoE 
session once per day, which is a flash renumbering eevent), some never 
renumber unless there is a big network change (I've had the same IPv6 
prefix now for a year).


The conclusion is that we need to create solutions that handle both 
these cases.


I agree with your conclusion, so the rest is pretty much a moot point 
for Homenet.




--
regards,
RayH

___
homenet mailing list
homenet@ietf.org
https://www.ietf.org/mailman/listinfo/homenet

Re: [homenet] IPv6 & firewall config in a home net

[Ted Lemon]

> On Sep 8, 2019, at 07:59, Michael Richardson  wrote:
> 
>> RID = F(Prefix, Net_Iface, Network_ID, DAD_Counter, secret_key)
> 
>> That was done to prevent tracking when people move between wifi
>> hotspots.
> 
> But, a host running a web server that wants to be in the same place could
> keep the same RID once generated.

Since the prefix is changing, keeping the host ID the same makes no difference. 
Presumably the server’s host name will be what’s invariant. 

___
homenet mailing list
homenet@ietf.org
https://www.ietf.org/mailman/listinfo/homenet

Re: [homenet] IPv6 & firewall config in a home net

[Michael Richardson]

Mikael Abrahamsson  wrote:
> This is the first time I've seen anyone make this claim (I guess
> related to GDPR). I've gone through GDPR review and talked to others
> who have done the same, and I from a GDPR point of view there is no
> reason to renumber on a regular basis. From what I can tell,
> renumbering at some frequency makes no difference from a GDPR point of
> view. The addresses are privacy sensitive regardless if you change them
> frequently or not.

It would be nice to get a public legal opinion published somewhere, so that
it can't be used as a marketing excuse.

> The conclusion is that we need to create solutions that handle both
> these cases.

Agreed, and it would be nice if it wasn't a flash renumber, which resetting
of the PPPoE session can causes.

-- 
]   Never tell me the odds! | ipv6 mesh networks [ 
]   Michael Richardson, Sandelman Software Works| network architect  [ 
] m...@sandelman.ca  http://www.sandelman.ca/|   ruby on rails[ 





signature.asc
Description: PGP signature
___
homenet mailing list
homenet@ietf.org
https://www.ietf.org/mailman/listinfo/homenet

Re: [homenet] IPv6 & firewall config in a home net

[Michael Richardson]

On Sep 2, 2019, at 1:47 PM, Michael Richardson  wrote:
> Assuming that the prefix change is make-before-break (which we
> do not clearly know how to do on the WAN side, I think), then the web
> server should configure with the same rfc7212 IID, but a new prefix.

To be clear, the issue of the make-before-break is on the WAN DHCPv6-PD side.
I believe that we concluded that it's possible to do in existing
specifications, but not well enough implemented at both sides (ISP/CPE)
device to depend upon.

Ted Lemon wrote on 05/09/2019 18:31:
> I don’t think there’s any need for the IID to be persistent.
> Make-before-break is accomplished by deprecating the old prefix when
> the new prefix is added.  This is trivial to do; whether it is in fact
> done is a different matter.  I think that at present the client would
> have to notice that it’s happened.

Ray Hunter (v6ops)  wrote:
> Agreed.

> Using RFC7217 will anyway almost certainly guarantee that the IID will
> also change if the prefix changes.

> The prefix is included in the function that generates candidate IID's.

>   RID = F(Prefix, Net_Iface, Network_ID, DAD_Counter, secret_key)

> That was done to prevent tracking when people move between wifi
> hotspots.

But, a host running a web server that wants to be in the same place could
keep the same RID once generated.

-- 
]   Never tell me the odds! | ipv6 mesh networks [ 
]   Michael Richardson, Sandelman Software Works| network architect  [ 
] m...@sandelman.ca  http://www.sandelman.ca/|   ruby on rails[ 



signature.asc
Description: PGP signature
___
homenet mailing list
homenet@ietf.org
https://www.ietf.org/mailman/listinfo/homenet