[dns-operations] Root-servers returning TC=1 after 5 NXDOMAINS

bert hubert bert.hubert at netherlabs.nl
Tue Feb 10 12:40:22 UTC 2015

On Tue, Feb 10, 2015 at 11:34:35AM +0000, ? Roy Arends wrote:
> > We've since tried to curtail our queries to the root severly, but we still
> > get TC=1 responses a lot, which slows down our resolution.
> Have you thought about running a local copy of the root zone?

More frequently now, yes. But I wonder if that is the intention. Is there an
official policy on root-servers that allow AXFR yet? Can one count on this

> > We shared our concerns with ISC, but it might be good to have a broader
> > discussion on if it makes sense to set the bar so very low.
> It doesn’t make sense to set the bar low on a single instance. What might
> happen is that due to some server selection algorithm, this server gets a
> penalty and the resolver flocks to other root-servers.

The penalty of TCP/IP by the way is so slight this does not change
nameserver selection in my case. If you'd count the cost of the original
query PLUS the TC=1 redirect, it might matter a bit more.


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