Dual stack hotspot/captive portal

Tim Chown tjc at ecs.soton.ac.uk
Thu Feb 24 22:57:35 CET 2011

On 24 Feb 2011, at 19:31, Darren Pilgrim wrote:

> On 2011-02-24 11:12, Simon Perreault wrote:
>> On 02/24/2011 02:10 PM, Darren Pilgrim wrote:
>>>> ...as long as the client doesn't change their IP after authenticating
>>>> to the portal page.
>>> That's a problem inherent with captive portals in general.
>> The thing is that it's much worse with IPv6 privacy extensions. And they
>> are enabled by default on Windows...
> The change rate is on the order of days.  The impact is pretty small given the application.

The default preferred lifetime is 1 day, with valid lifetime 7 days.

I think the minimum you can set preferred lifetime to is about 10 minutes, so you could use up to 150 different IPv6 addresses a day as privacy source addresses in Windows 7, if you didn't sleep :)

And that's on top of the static global address that the host would usually be reached by.


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