🛡️ Nameserver Resilience

Domains whose DNS hangs on a single nameserver, address, network or AS · all insights

DNS should never hang on one server. This page counts the .dk domains whose nameservers share a single host, address, network or autonomous system, the single points of failure that turn one outage into a dead domain. Data comes from our own scanners, which re-resolve every .dk domain in the zone roughly once a week.

🛡️ Single points of failure

1,185,859 working delegations with resolvable nameservers (lame excluded)
Every nameserver is on…DomainsShareWhy it matters
A single nameserver host1470.01%Any outage or mistake on that host takes the domain offline; RFC 1034 asks for at least two.
A single nameserver address1,3060.11%Several NS names, but they all resolve to one IP, so they are really one server.
One IPv4 /24 and no IPv610,7960.91%All nameservers share one network: a routing problem there takes them all down.
One autonomous system758,38264.0%Common and usually fine with a large provider, but one network outage still takes all nameservers down.
No IPv6 nameserver85,8087.2%IPv6-only resolvers cannot reach the zone.

Click a row to list its domains (computed 2026-10-01 08:10).

📋 One autonomous system

758,382 domains
DomainNameservers and addresses
49.dkada.ns.cloudflare.com 108.162.192.54 AS13335, 172.64.32.54 AS13335, 173.245.58.54 AS13335, 2606:4700:50::adf5:3a36 AS13335, 2803:f800:50::6ca2:c036 AS13335, 2a06:98c1:50::ac40:2036 AS13335
tanner.ns.cloudflare.com 108.162.195.97 AS13335, 162.159.44.97 AS13335, 172.64.35.97 AS13335, 2606:4700:58::a29f:2c61 AS13335, 2803:f800:50::6ca2:c361 AS13335, 2a06:98c1:50::ac40:2361 AS13335
49134060.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
49135584.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
49145555.dkns1.curanet.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.curanet.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
49147232.dkgate.profdoc.dk 80.62.243.243 AS3292
ns.profdoc.dk 80.62.243.242 AS3292
49193319.dkns1.curanet.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.curanet.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
49210263.dkgate.profdoc.dk 80.62.243.243 AS3292
ns.profdoc.dk 80.62.243.242 AS3292
49210813.dkdns1.cscdns.net 156.154.130.100 AS12008, 2610:a1:1022::100 AS12008
dns2.cscdns.net 156.154.131.100 AS12008, 2610:a1:1023::100 AS12008
49213066.dkns1.curanet.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.curanet.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
49213709.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
49220603.dkelsa.ns.cloudflare.com 108.162.192.111 AS13335, 172.64.32.111 AS13335, 173.245.58.111 AS13335, 2606:4700:50::adf5:3a6f AS13335, 2803:f800:50::6ca2:c06f AS13335, 2a06:98c1:50::ac40:206f AS13335
rajeev.ns.cloudflare.com 108.162.193.224 AS13335, 172.64.33.224 AS13335, 173.245.59.224 AS13335, 2606:4700:58::adf5:3be0 AS13335, 2803:f800:50::6ca2:c1e0 AS13335, 2a06:98c1:50::ac40:21e0 AS13335
49224922.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4930-maribo.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4930.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
4930maribo.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4944.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
4945.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4953.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4960.dkns1.curanet.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.curanet.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
49700077.dkdave.ns.cloudflare.com 108.162.193.109 AS13335, 172.64.33.109 AS13335, 173.245.59.109 AS13335, 2606:4700:58::adf5:3b6d AS13335, 2803:f800:50::6ca2:c16d AS13335, 2a06:98c1:50::ac40:216d AS13335
vera.ns.cloudflare.com 108.162.192.147 AS13335, 172.64.32.147 AS13335, 173.245.58.147 AS13335, 2606:4700:50::adf5:3a93 AS13335, 2803:f800:50::6ca2:c093 AS13335, 2a06:98c1:50::ac40:2093 AS13335
49703831.dkns01.danskinternet.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns02.danskinternet.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
4a-consult.dkns1.bdm.microsoftonline.com 13.107.236.208 AS8075, 2603:1061:0:700::d0 AS8075
ns2.bdm.microsoftonline.com 150.171.21.208 AS8075, 2620:1ec:8ec:700::d0 AS8075
ns3.bdm.microsoftonline.com 204.14.183.208 AS8075, 2a01:111:4000:700::d0 AS8075
ns4.bdm.microsoftonline.com 208.84.5.208 AS8075, 2620:1ec:bda:700::d0 AS8075
4a.dkns1.eurodns.com 199.167.66.107 AS23393, 2610:1c8:b002::107 AS23393
ns2.eurodns.com 104.37.178.107 AS23393, 2610:1c8:b001::107 AS23393
ns3.eurodns.com 199.167.66.108 AS23393, 2610:1c8:b002::108 AS23393
ns4.eurodns.com 104.37.178.108 AS23393, 2610:1c8:b001::108 AS23393
4a4b.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4aadviser.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4aarstider.dkns.dandomain.dk 185.25.141.3 AS48854, 2a02:2339:4006:109::dd AS48854
ns2.dandomain.dk 2a02:2339:1:108::dd:dd AS48854, 91.197.248.66 AS48854
4abyggepartner.dkns1.eurodns.com 199.167.66.107 AS23393, 2610:1c8:b002::107 AS23393
ns2.eurodns.com 104.37.178.107 AS23393, 2610:1c8:b001::107 AS23393
ns3.eurodns.com 199.167.66.108 AS23393, 2610:1c8:b002::108 AS23393
ns4.eurodns.com 104.37.178.108 AS23393, 2610:1c8:b001::108 AS23393
4achievers.dkns61.domaincontrol.com 2603:5:2153::20 AS44273, 97.74.101.32 AS44273
ns62.domaincontrol.com 173.201.69.32 AS44273, 2603:5:2253::20 AS44273
4advice.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4agger.dkns.dandomain.dk 185.25.141.3 AS48854, 2a02:2339:4006:109::dd AS48854
ns2.dandomain.dk 2a02:2339:1:108::dd:dd AS48854, 91.197.248.66 AS48854
4aid.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
4all.dkns3.nordicway.dk 2a01:4f8:c2c:d3c0::1 AS24940, 78.47.45.64 AS24940
ns4.nordicway.dk 2a01:4f8:c010:24a2::1 AS24940, 78.47.56.84 AS24940
4allrunners.dkns.scannet2.dk 185.25.141.9 AS48854, 2a02:2339:4006:10d::4171:4171 AS48854
ns2.scannet2.dk 2a02:2339:1:112:0:5:1:b11 AS48854, 91.197.248.72 AS48854
4allsport.dkns4.wixdns.net 216.239.36.101 AS15169
ns5.wixdns.net 216.239.38.101 AS15169
4amigos.dkns1.curanet.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.curanet.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
4aminvest.dkns4.dns-123.net 35.198.132.83 AS396982
ns5.dns-123.net 35.187.184.173 AS396982
ns6.dns-123.net 35.228.54.1 AS396982
4andersen.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4ap.dkdakota.ns.cloudflare.com 108.162.195.79 AS13335, 162.159.44.79 AS13335, 172.64.35.79 AS13335, 2606:4700:58::a29f:2c4f AS13335, 2803:f800:50::6ca2:c34f AS13335, 2a06:98c1:50::ac40:234f AS13335
violet.ns.cloudflare.com 108.162.192.237 AS13335, 172.64.32.237 AS13335, 173.245.58.237 AS13335, 2606:4700:50::adf5:3aed AS13335, 2803:f800:50::6ca2:c0ed AS13335, 2a06:98c1:50::ac40:20ed AS13335
4areason.dkns.dandomain.dk 185.25.141.3 AS48854, 2a02:2339:4006:109::dd AS48854
ns2.dandomain.dk 2a02:2339:1:108::dd:dd AS48854, 91.197.248.66 AS48854
4arkitekterrådgivning.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4asics.dkns.dandomain.dk 185.25.141.3 AS48854, 2a02:2339:4006:109::dd AS48854
ns2.dandomain.dk 2a02:2339:1:108::dd:dd AS48854, 91.197.248.66 AS48854
4audit.dkcloe.ns.cloudflare.com 108.162.192.86 AS13335, 172.64.32.86 AS13335, 173.245.58.86 AS13335, 2606:4700:50::adf5:3a56 AS13335, 2803:f800:50::6ca2:c056 AS13335, 2a06:98c1:50::ac40:2056 AS13335
earl.ns.cloudflare.com 108.162.193.161 AS13335, 172.64.33.161 AS13335, 173.245.59.161 AS13335, 2606:4700:58::adf5:3ba1 AS13335, 2803:f800:50::6ca2:c1a1 AS13335, 2a06:98c1:50::ac40:21a1 AS13335
4b-byg.dkgabriella.ns.cloudflare.com 108.162.194.134 AS13335, 162.159.38.134 AS13335, 172.64.34.134 AS13335, 2606:4700:50::a29f:2686 AS13335, 2803:f800:50::6ca2:c286 AS13335, 2a06:98c1:50::ac40:2286 AS13335
mitch.ns.cloudflare.com 108.162.193.208 AS13335, 172.64.33.208 AS13335, 173.245.59.208 AS13335, 2606:4700:58::adf5:3bd0 AS13335, 2803:f800:50::6ca2:c1d0 AS13335, 2a06:98c1:50::ac40:21d0 AS13335
4b-capital.dkns1.wannafind.dk 185.25.141.6 AS48854, 2a02:2339:4006:103:1c:3f6d:daba:dee AS48854
ns2.wannafind.dk 2a02:2339:1:104::daba:daa AS48854, 91.197.248.69 AS48854
4b.dkns.scannet2.dk 185.25.141.9 AS48854, 2a02:2339:4006:10d::4171:4171 AS48854
ns2.scannet2.dk 2a02:2339:1:112:0:5:1:b11 AS48854, 91.197.248.72 AS48854
4baby.dkns.dandomain.dk 185.25.141.3 AS48854, 2a02:2339:4006:109::dd AS48854
ns2.dandomain.dk 2a02:2339:1:108::dd:dd AS48854, 91.197.248.66 AS48854
4ball.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
4bang.dkjocelyn.ns.cloudflare.com 108.162.192.174 AS13335, 172.64.32.174 AS13335, 173.245.58.174 AS13335, 2606:4700:50::adf5:3aae AS13335, 2803:f800:50::6ca2:c0ae AS13335, 2a06:98c1:50::ac40:20ae AS13335
kyree.ns.cloudflare.com 108.162.195.207 AS13335, 162.159.44.207 AS13335, 172.64.35.207 AS13335, 2606:4700:58::a29f:2ccf AS13335, 2803:f800:50::6ca2:c3cf AS13335, 2a06:98c1:50::ac40:23cf AS13335
4barista.dkns1.websupport.sk 2a10:bbc0::11 AS25234, 45.10.97.11 AS25234
ns2.websupport.sk 185.71.159.12 AS25234, 2a02:250:3::12 AS25234
ns3.websupport.sk 2a10:bbc0::13 AS25234, 45.10.97.13 AS25234
4bay.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78 AS48854
ns2.simply.com 185.25.141.15 AS48854, 2a02:2339:4006:101::4562:4562 AS48854
ns3.simply.com 91.197.248.79 AS48854
ns4.simply.com 91.197.248.80 AS48854
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