Re: [DNSOP] New draft on delegation revalidation

[Paul Vixie <[e-mail]>]

On Saturday, 11 April 2020 17:02:07 UTC Shumon Huque wrote:
> On Sat, Apr 11, 2020 at 12:33 PM Stephane Bortzmeyer <[e-mail]>
> wrote:
> > ...
> > 
> > I don't think that you answer Brian's idea. The way I've read his
> > idea, he suggested, when a resolver detects a lame server (or when all
> > servers are lame?), to go back to the parent and to ask again the NS
> > set, to see if there is a new and better list.
> 
> Fair enough. If all the servers are lame, that sounds like a reasonable
> strategy.
> 
> If only some are lame, and there are still usable servers available, I
> suspect resolver implementers won't want to revalidate to avoid the
> potential additional performance/latency costs.

if this is part of a larger strategy of lame delegation holddown, i think it's 
a good idea and even in-scope for the current draft. but without the holddown, 
it becomes a DDoS against the delegating zone's authority servers. (BIND4 had 
that at one point, and it was un-pretty.) when revalidation fails, we can 
argue whether to "rm -r" the cache contents at that delegation point, but we 
must always prevent subsequent revalidation for a period (randomly chosen) in 
a range of several minutes.

-- 
Paul