Re: [GROW] Eric Rescorla's No Objection on draft-ietf-grow-bgp-reject-08: (with COMMENT)

[Eric Rescorla <[e-mail]>]

On Thu, Jun 8, 2017 at 1:34 AM, Job Snijders <[e-mail]> wrote:

> Hi Eric,
>
> On Tue, Jun 06, 2017 at 10:50:01AM -0700, Eric Rescorla wrote:
> > ----------------------------------------------------------------------
> > COMMENT:
> > ----------------------------------------------------------------------
> >
> > I am having a little trouble reading Appendix A.
> >
> > If I understand correctly, the idea is:
> >
> > - In version N, you have a behavior X
> > - In version N+1, you introduce a setting S with default value S=X
> > - In version N+2 you change the default to S=!X
> >
> > However, the text says that "installations upgraded from release N+1
> > will adhere to the previous insecure behavior"
> >
> > Do you need to say that in N+1, you save the value S=X so that in N+1,
> > it continues to apply?
>
> If in N+1 you save S=X, then in N+2, if S is defined as X, behaviour X
> will apply.


Well, yes.



> If S is not defined, or defined otherwise (like with a fresh
> install, not an upgrade), you will have !X behaviour.
>

Yes.

My question is whether in the N+1/N+2 paradigm you are proposing that in
N+1 you save S=X.

-Ekr


> It kind of depends on the implementation and configuration paradigm
> whether this advice can be applicable, hence why we flagged it as "This
> appendix is non-normative."
>
> Kind regards,
>
> Job
>