[Mesh] Changing your MAC address

[Mitar]

Hi!

Of course you can get the same IP address if you keep the same MAC. If
you change MAC then there is no way for DHCP to assign you the same IP.
(Not really true, it could based on the client name you probably
broadcast with your DHCP request and which is as well a privacy leak.)
And even if it would assign you the same IP, it would then link you to
your previous MAC because of this, so you do not want this, if you care
about MAC privacy.

Anyway, we are talking here about IPv6, so you do not use DHCP but
simply prefix. And then a way to append MAC to that prefix. So changing
MAC means changing IP as well (if you keep old one, then you again link
your new MAC to your old one, even if you use something as hash function
to obfuscate your MAC addresses).


Mitar

> TCP sessions get reset when you get a new lease on a different IP.
> 
> Hopefully short lease times comes with giving you the same IP if you
> stay connected and keep re-acquiring leases. But I've encountered
> equipment that doesn't.
> 
> 
> 
> -a
> 
> 
> On 20 November 2013 13:47, Steve Berl <steveberl at gmail.com> wrote:
>> It makes a lot of sense that a network with MAC hopping devices would need a
>> DHCP server with short lease times.
>>
>> How do short lease times impact devices that are not changing their MAC
>> addresses?
>>
>> -steve
>>
>>
>> On Wed, Nov 20, 2013 at 12:18 PM, Yardena Cohen <yardenack at gmail.com> wrote:
>>>
>>> Inspired by last week's conversation, I experimented with MAC
>>> randomization on my laptop. And I DoS'd my own network by exhausting
>>> its DHCP pool.
>>>
>>> My very naive script reset the MAC after every network hiccup, so the
>>> router kept seeing an entirely new device and giving it a new IP
>>> address. Slowly. Until they were all gone. I "solved" my problem the
>>> stupid way by rebooting the router and lowering the DHCP timeout from
>>> 24 to 3 hours.
>>>
>>> A production script would be clever about resetting it only on new
>>> associations, and not on every brief reassociation. However, still
>>> something to keep in mind when deploying networks that encourage this
>>> sort of thing. ;)
>>> _______________________________________________
>>> mesh mailing list
>>> mesh at lists.sudoroom.org
>>> http://lists.sudoroom.org/listinfo/mesh
>>
>>
>>
>>
>> --
>> -steve
>>
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>>
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