[atlas] Probes suffering DNS interception?

On Thu, Dec 10, 2020 at 05:29:46PM +0000,
 Ray Bellis <ray at isc.org> wrote 
 a message of 20 lines which said:

> Is there any RIPE policy about whether nodes that are subject to DNS
> interception should be excluded from results (or maybe even dropped
> altogether) ?

I disagree. The point of RIPE Atlas probes is to test the Internet AS
IT IS, not as we would like it to be. (Otherwise, I would drop the
probes behind NAT…)

> While these probes are perhaps still useful for ping and traceroute
> tests, they are effectively useless for DNS related tests other than as
> a proxy measure for how prevalent that practise actually is.

Which is an important use.

> If there was a heuristic that could be applied on the probe itself or
> within the RIPE data collector that tagged the probe as having "bad DNS"
> that would help a lot.

Adding a tag is indeed a good idea, but not excluding or dropping
these probes.