On Thu, Jul 20, 2017 at 02:20:39PM +0200, Chris Amin <camin@ripe.net> wrote a message of 90 lines which said:
it would be useful to have SOA queries from all probes with the NSID EDNS option set, in order to be able to match up responses with the particular responding instances
It is also useful to detect rogue root name servers (quite common with anycast) or transparent DNS proxies. (Measurement #9209448 finds several probes asking a rogue L-root, which has no NSID support, or located behind a middlebox which strips NSID. Check probes 23621,19770, 24890, 26328, 27059, 27080, 27843, 33806, 21570,14272, 13660, 17775, 17841, 26587, 30847, 11410, 23438, 29814, 13719, 21140, 25189, 25197. For some, the SOA serial number is so old that it is probably a rogue root name server. Also, one probe, 28846, finds a server replying with an abnormal NSID, which is not the normal from L-root.)
I also find useful to match id.server./hostname.bind. queries against the NSID results (à-la-nsidenumerator, see flag --id-server, https://github.com/insomniacslk/nsidenumerator )