Re: problem statement [was Re: New Version Notification for draft-hinden-ipv4flag-00.txt]

[David Farmer <[e-mail]>]

On Mon, Nov 20, 2017 at 7:42 PM, Brian E Carpenter <
[e-mail]> wrote:

> Another response to multiple points:
>
...

> > 1. Security exposure; the inverse of the problems discussed in RFC7123,
> > basically malicious or accidental IPv4 service.
> > 2. Residual IPv4 traffic, especially broadcast traffic; DHCP solicits,
> > IPv4-LL, ARP, service discovery, etc...
>
> The proposal addresses only one thing: attempting to reduce
> futile IPv4 traffic. It neither creates nor blocks IPv4 traffic.
>

That might be, but this thread is about a problem statement, and
conceivably that could add to the draft. Anyway we shouldn't ignore #1, I
think at least something should be said in the security considerations
section on the subject.  Also since this uses RAs, the security
considerations section should probably say something about rogue RAs and
the options to protect against them.


> > In very high dentistry and therefore
> > typically congested WiFi environments...
>
> A new view of dentist's office networking ;-)
>

Serendipitous and amusing autocorrecto :)

....

> > if IPv4 appears you probably want to start
> > using it after a reasonable amount of time.
>
> Indeed. And under the proposal, any RA with flag==0 would be
> an instant trigger to wake up the IPv4 stack. (And no, that
> isn't a serious DOS risk, since it is no worse than what
> we have today.)
>

Should Router Preference [RFC4191] play in this equation?  Should an RA
with a Router Preference = High and this flag = 1 be overridden by
different RA with Router Preference = Low and this flag = 0. I'm not sure I
have an answer, but this probably should be addressed in the draft either
way.

I bring this up as setting Router Preference to High is a common technique
to help protect against at least accidental RAs. Yes malicious RAs can use
a Router Preference of High, but all rogue RAs I've seen in the wild had a
medium (default) Router Preference.

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