🛡️ 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

1,185,715 working delegations with resolvable nameservers (lame excluded)
Every nameserver is on…DomainsShareWhy it matters
A single nameserver host1490.01%Any outage or mistake on that host takes the domain offline; RFC 1034 asks for at least two.
A single nameserver address1,3130.11%Several NS names, but they all resolve to one IP, so they are really one server.
One IPv4 /24 and no IPv610,8080.91%All nameservers share one network: a routing problem there takes them all down.
One autonomous system755,25063.7%Common and usually fine with a large provider, but one network outage still takes all nameservers down.
No IPv6 nameserver85,9817.3%IPv6-only resolvers cannot reach the zone.

Click a row to list its domains (computed 2026-09-30 06:38).

📋 One autonomous system

755,250 domains
DomainNameservers and addresses
2100happiness.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
2100lvs.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
2100optik.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
2100ø.dkdell.ns.cloudflare.com 108.162.192.94 AS13335, 172.64.32.94 AS13335, 173.245.58.94 AS13335, 2606:4700:50::adf5:3a5e AS13335, 2803:f800:50::6ca2:c05e AS13335, 2a06:98c1:50::ac40:205e AS13335
karl.ns.cloudflare.com 108.162.193.190 AS13335, 172.64.33.190 AS13335, 173.245.59.190 AS13335, 2606:4700:58::adf5:3bbe AS13335, 2803:f800:50::6ca2:c1be AS13335, 2a06:98c1:50::ac40:21be AS13335
2102.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
2106.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
2108.dkelma.ns.cloudflare.com 108.162.192.154 AS13335, 172.64.32.154 AS13335, 173.245.58.154 AS13335, 2606:4700:50::adf5:3a9a AS13335, 2803:f800:50::6ca2:c09a AS13335, 2a06:98c1:50::ac40:209a AS13335
greg.ns.cloudflare.com 108.162.193.115 AS13335, 172.64.33.115 AS13335, 173.245.59.115 AS13335, 2606:4700:58::adf5:3b73 AS13335, 2803:f800:50::6ca2:c173 AS13335, 2a06:98c1:50::ac40:2173 AS13335
210reol.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
211.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
2110.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
2112.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
21212120.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
21221281.dkns1.dnsatconviator.com 185.106.119.62 AS201926
ns2.dnsatconviator.com 185.106.119.63 AS201926
ns3.dnsatconviator.com 185.106.119.64 AS201926
2123.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
21291112.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
213.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
214.dkdimitris.ns.cloudflare.com 108.162.195.6 AS13335, 162.159.44.6 AS13335, 172.64.35.6 AS13335, 2606:4700:58::a29f:2c06 AS13335, 2803:f800:50::6ca2:c306 AS13335, 2a06:98c1:50::ac40:2306 AS13335
ursula.ns.cloudflare.com 108.162.194.191 AS13335, 162.159.38.191 AS13335, 172.64.34.191 AS13335, 2606:4700:50::a29f:26bf AS13335, 2803:f800:50::6ca2:c2bf AS13335, 2a06:98c1:50::ac40:22bf AS13335
2143.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
21460850.dkns1.azehosting.net 2a01:4f8:13b:3146::1 AS24940, 94.130.138.185 AS24940
ns2.azehosting.net 2a01:4f8:c17:5f0a::2 AS24940, 88.99.15.5 AS24940
ns3.azehosting.net 2a01:4f8:c17:6a6e::2 AS24940, 88.99.39.181 AS24940
21470995.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
2150flatiron.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
2150nordhavn.dkns1.webhotel.net 217.30.38.181 AS47292
ns2.webhotel.net 217.30.38.27 AS47292
217.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
21703655.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
21722642.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
21746574.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
21800643.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
21841189.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
21advisory.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
21bit.dksandra.ns.cloudflare.com 108.162.194.34 AS13335, 162.159.38.34 AS13335, 172.64.34.34 AS13335, 2606:4700:50::a29f:2622 AS13335, 2803:f800:50::6ca2:c222 AS13335, 2a06:98c1:50::ac40:2222 AS13335
vicente.ns.cloudflare.com 108.162.195.239 AS13335, 162.159.44.239 AS13335, 172.64.35.239 AS13335, 2606:4700:58::a29f:2cef AS13335, 2803:f800:50::6ca2:c3ef AS13335, 2a06:98c1:50::ac40:23ef AS13335
21blackjack.dkadel.ns.cloudflare.com 108.162.192.55 AS13335, 172.64.32.55 AS13335, 173.245.58.55 AS13335, 2606:4700:50::adf5:3a37 AS13335, 2803:f800:50::6ca2:c037 AS13335, 2a06:98c1:50::ac40:2037 AS13335
vick.ns.cloudflare.com 108.162.193.244 AS13335, 172.64.33.244 AS13335, 173.245.59.244 AS13335, 2606:4700:58::adf5:3bf4 AS13335, 2803:f800:50::6ca2:c1f4 AS13335, 2a06:98c1:50::ac40:21f4 AS13335
21casino.dksandra.ns.cloudflare.com 108.162.194.34 AS13335, 162.159.38.34 AS13335, 172.64.34.34 AS13335, 2606:4700:50::a29f:2622 AS13335, 2803:f800:50::6ca2:c222 AS13335, 2a06:98c1:50::ac40:2222 AS13335
vicente.ns.cloudflare.com 108.162.195.239 AS13335, 162.159.44.239 AS13335, 172.64.35.239 AS13335, 2606:4700:58::a29f:2cef AS13335, 2803:f800:50::6ca2:c3ef AS13335, 2a06:98c1:50::ac40:23ef AS13335
21century.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
21cf.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
21h.dkns1.simply.com 2a02:2339:1:15c::4562:4562 AS48854, 91.197.248.78
ns2.simply.com 185.25.141.15, 2a02:2339:4006:101::4562:4562
ns3.simply.com 91.197.248.79
ns4.simply.com 91.197.248.80
21k.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
21kcasino.dkdee.ns.cloudflare.com 108.162.192.93 AS13335, 172.64.32.93 AS13335, 173.245.58.93 AS13335, 2606:4700:50::adf5:3a5d AS13335, 2803:f800:50::6ca2:c05d AS13335, 2a06:98c1:50::ac40:205d AS13335
harvey.ns.cloudflare.com 108.162.195.152 AS13335, 162.159.44.152 AS13335, 172.64.35.152 AS13335, 2606:4700:58::a29f:2c98 AS13335, 2803:f800:50::6ca2:c398 AS13335, 2a06:98c1:50::ac40:2398 AS13335
21kfor11.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
21leadership.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
21montering.dkudns1.cscdns.net 2001:502:f3ff::201 AS12008, 204.74.66.1 AS12008
udns2.cscdns.uk 2001:502:4612::201 AS12008, 204.74.111.1 AS12008
21n.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
21nova.dkdns1.idp365.net 162.159.27.131 AS13335, 2400:cb00:2049:1::a29f:1b83 AS13335
dns2.idp365.net 162.159.48.3 AS13335, 2400:cb00:2049:1::a29f:3003 AS13335
dns3.idp365.net 162.159.49.254 AS13335, 2400:cb00:2049:1::a29f:31fe AS13335
21o.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
21risk.dkalla.ns.cloudflare.com 108.162.192.62 AS13335, 172.64.32.62 AS13335, 173.245.58.62 AS13335, 2606:4700:50::adf5:3a3e AS13335, 2803:f800:50::6ca2:c03e AS13335, 2a06:98c1:50::ac40:203e AS13335
carl.ns.cloudflare.com 108.162.193.106 AS13335, 172.64.33.106 AS13335, 173.245.59.106 AS13335, 2606:4700:58::adf5:3b6a AS13335, 2803:f800:50::6ca2:c16a AS13335, 2a06:98c1:50::ac40:216a AS13335
21roser.dkalexis.ns.cloudflare.com 108.162.193.60 AS13335, 172.64.33.60 AS13335, 173.245.59.60 AS13335, 2606:4700:58::adf5:3b3c AS13335, 2803:f800:50::6ca2:c13c AS13335, 2a06:98c1:50::ac40:213c AS13335
joyce.ns.cloudflare.com 108.162.194.14 AS13335, 162.159.38.14 AS13335, 172.64.34.14 AS13335, 2606:4700:50::a29f:260e AS13335, 2803:f800:50::6ca2:c20e AS13335, 2a06:98c1:50::ac40:220e AS13335
21skills.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
21st-century-classic.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
21stcenturycity.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
21ø.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
22-bet-dk.dkcarter.ns.cloudflare.com 108.162.193.80 AS13335, 172.64.33.80 AS13335, 173.245.59.80 AS13335, 2606:4700:58::adf5:3b50 AS13335, 2803:f800:50::6ca2:c150 AS13335, 2a06:98c1:50::ac40:2150 AS13335
dora.ns.cloudflare.com 108.162.192.108 AS13335, 172.64.32.108 AS13335, 173.245.58.108 AS13335, 2606:4700:50::adf5:3a6c AS13335, 2803:f800:50::6ca2:c06c AS13335, 2a06:98c1:50::ac40:206c AS13335
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