Dear list, while troubleshooting DNS issues on the Google network yesterday [1] we found that RIPE Atlas probes did not recover after Google fixed the issue, we kept seeing SERVFAIL answers on the RIPE Atlas probes. We now know that those ATLAS results are bogus. For example google.us against 8.8.4.4 https://atlas.ripe.net/measurements/30456676/#probes google.us against 1.1.1.1 https://atlas.ripe.net/measurements/30464549/#probes zoom.us against 8.8.8.8 https://atlas.ripe.net/measurements/30464774/#probes zoom.us against 1.1.1.1 https://atlas.ripe.net/measurements/30464777/#probes amazon.com on quad9 https://atlas.ripe.net/measurements/30479180/#probes amazon.com on quad1 https://atlas.ripe.net/measurements/30479179/#probes Even amazon.com on quad9 and quad1 has numerous SERVFAIL. To reproduce, just try to resolve zoom.us or google.us against 8.8.8.8 or 1.1.1.1 on your probe. Any recommendations on how we could troubleshoot this? [1] https://puck.nether.net/pipermail/outages/2021-May/013648.html