Perhaps a newbie question: I am doing a DNS measurement and almost all probes return NXDOMAIN (expected), yet one probe returns NOERROR. How can I determine which DNS server it is using to provide a NOERROR? See attached json. Thanks, Hank
Hi Hank, While I can't answer your inquiry, unfortunately, I can tell you that there's no such thing as a stupid or newbish question here. I hope I can speak on behalf of the Atlas community when I say that we're a really open and supportive community to anyone working with Internet measurements, so please don't hesitate to ask in the future! Warm regards, -Michael On Tue, Apr 29, 2025 at 8:28 AM Hank Nussbacher <hank@interall.co.il> wrote:
Perhaps a newbie question:
I am doing a DNS measurement and almost all probes return NXDOMAIN (expected), yet one probe returns NOERROR.
How can I determine which DNS server it is using to provide a NOERROR?
See attached json.
Thanks,
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On 29.04.2025, at 08:28, Hank Nussbacher <hank@interall.co.il> wrote:
How can I determine which DNS server it is using to provide a NOERROR? You can query o-o.myaddr.l.google.com. for TXT records or myip.opendns.com <http://myip.opendns.com/>, but for this you’d better querying both A and AAAA records.
-e
On Tue, Apr 29, 2025 at 09:07:04AM +0200, Endre Szabo <endre.szabo@ripeatlas-ml-nerudrr.rediremail.com> wrote a message of 13 lines which said:
How can I determine which DNS server it is using to provide a NOERROR? You can query o-o.myaddr.l.google.com. for TXT records or myip.opendns.com <http://myip.opendns.com/>
Or resolver.00f.net or _country.pool.ntp.org or whoami.v4.powerdns.org or whoami.fastly.net or whoami.akamai.net or resolver-identity.cloudfront.net or whoami.ultradns.net. It is apparently a Google resolver: % blaeu-resolve --nsid --probes 1006193 --type TXT ip.dyn.bortzmeyer.fr ["172.217.32.208" NSID: None;] : 1 occurrences Test #100371567 done at 2025-04-29T07:36:26Z This IP address is a Google one. Apparently, the resolver used by this probe, 10.5.21.3, is not Google - it has no NSID - but forwards to Google, may be after applying a local blacklist. Another test showed the address 2620:171:75:f003:9999::244, which belongs to PCH, so may be 10.5.21.3 is load balancing between gpdns and quad9.
participants (4)
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Endre Szabo -
Hank Nussbacher -
Michael J. Oghia -
Stephane Bortzmeyer