Proposal: Enable IPv6 Privacy Extensions (RFCs 3041/4941) by default

[Max Laier]

Am Di, 10.06.2008, 07:07, schrieb Doug Barton:
> By default, IPv6 stateless autoconfiguration creates a 64 bit hostid
> for each interface based on the mac address (for ethernet, but for us
> that's the common case). This is convenient since if you're using RA
> neither the user nor the admin has to do anything to get the node on
> line, it "just works." There is a privacy issue with this however,
> because this identifier is created in such a way as to make it
> globally unique, the machine (and therefore in almost all cases the
> user) can be tracked by third parties such as web sites, even if they
> move from one network prefix to another, such as with a laptop.
>
> To address those privacy concerns RFC 3041 was written, and eventually
> obsoleted by RFC 4941. ftp://ftp.rfc-editor.org/in-notes/rfc4941.txt
> Our IPv6 implementation comes with the code to enable this feature,
> but by default it is turned off. My proposal is to enable it by
> default, and give the user a knob in rc.conf to turn it off. I'm
> interested in any arguments y'all might have for or against. To test
> this is pretty simple, add the following to /etc/sysctl.conf:
> net.inet6.ip6.use_tempaddr=1
> net.inet6.ip6.prefer_tempaddr=1
>
> The "normal" EUI-64-based address will still be configured, but there
> will also be a random identifier added to the interface as an alias,
> and outgoing traffic will go out from that address.
>
> In way of comparison, windows starting with XP enables this feature by
> default for clients, and has a knob to enable it for servers. I'd be
> interested to hear what other systems do.
>
>
> Thoughts?

All for it.  Are you, however, sure that we implement RFC 4941 fully?  I
think there are some configuration parameters missing.  Also, I seem to
recall that our DAD wasn't quite state-of-the-art, yet.  Finally, any
chance I can get you to implement the socket options in RFC 5014, so that
programs have can force a temp/static address if they so choose -
independent of the global setting.

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