On Fri, Dec 21, 2018 at 02:48:03PM +0000, Steven Surdock via Outages <outages@outages.org> wrote a message of 13 lines which said:
Anyone know what is going on with The US Naval Observatory? Usno.navy.mil appears to be completely unresolvable.
Indeed, their four name servers do not reply to most packets. Sometimes, it works: % check-soa -i usno.navy.mil charon.usno.navy.mil. 199.211.133.5: OK: 201709123 (180 ms) metis.usnogps.navy.mil. Cannot get the IPv4 address: read udp 127.0.0.1:57410->127.0.0.1:53: i/o timeout psyche.usno.navy.mil. 192.5.41.214: OK: 201709123 (181 ms) tycho.usnogps.navy.mil. Cannot get the IPv6 address: read udp 127.0.0.1:59763->127.0.0.1:53: i/o timeout And sometimes not: % check-soa -i usno.navy.mil charon.usno.navy.mil. 199.211.133.5: ERROR: read udp 10.10.86.133:50346->199.211.133.5:53: i/o timeout metis.usnogps.navy.mil. Cannot get the IPv4 address: read udp 127.0.0.1:51404->127.0.0.1:53: i/o timeout psyche.usno.navy.mil. 192.5.41.214: ERROR: read udp 10.10.86.133:34181->192.5.41.214:53: i/o timeout tycho.usnogps.navy.mil. Cannot get the IPv6 address: read udp 127.0.0.1:50038->127.0.0.1:53: i/o timeout RIPE Atlas probes see a majority of failures: % blaeu-resolve -r 250 -q NS usno.navy.mil [ERROR: NXDOMAIN] : 150 occurrences [ERROR: SERVFAIL] : 14 occurrences [charon.usno.navy.mil. metis.usnogps.navy.mil. psyche.usno.navy.mil. tycho.usnogps.navy.mil.] : 81 occurrences Test #18414784 done at 2018-12-21T14:58:04Z May be a DoS? But I'm surprised by the number of NXDOMAIN (unresponding servers should trigger SERVFAIL or timeout).