🛡️ 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

1,186,285 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 address1,3030.11%Several NS names, but they all resolve to one IP, so they are really one server.
One IPv4 /24 and no IPv610,7740.91%All nameservers share one network: a routing problem there takes them all down.
One autonomous system758,93564.0%Common and usually fine with a large provider, but one network outage still takes all nameservers down.
No IPv6 nameserver85,7527.2%IPv6-only resolvers cannot reach the zone.

Click a row to list its domains (computed 2026-10-01 14:22).

📋 One autonomous system

758,935 domains
DomainNameservers and addresses
4rf.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
4rfs.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
4rooms.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
4roses.dklila.ns.cloudflare.com 108.162.192.186 AS13335, 172.64.32.186 AS13335, 173.245.58.186 AS13335, 2606:4700:50::adf5:3aba AS13335, 2803:f800:50::6ca2:c0ba AS13335, 2a06:98c1:50::ac40:20ba AS13335
west.ns.cloudflare.com 108.162.193.247 AS13335, 172.64.33.247 AS13335, 173.245.59.247 AS13335, 2606:4700:58::adf5:3bf7 AS13335, 2803:f800:50::6ca2:c1f7 AS13335, 2a06:98c1:50::ac40:21f7 AS13335
4runner.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
4runners.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
4s-online.dkamber.ns.cloudflare.com 108.162.192.64 AS13335, 172.64.32.64 AS13335, 173.245.58.64 AS13335, 2606:4700:50::adf5:3a40 AS13335, 2803:f800:50::6ca2:c040 AS13335, 2a06:98c1:50::ac40:2040 AS13335
cullen.ns.cloudflare.com 108.162.195.91 AS13335, 162.159.44.91 AS13335, 172.64.35.91 AS13335, 2606:4700:58::a29f:2c5b AS13335, 2803:f800:50::6ca2:c35b AS13335, 2a06:98c1:50::ac40:235b AS13335
4s.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
4safety.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
4salg.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
4sat.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
4seasonclean.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
4seasons.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
4seasonsdesign.dknoel.ns.cloudflare.com 108.162.193.216 AS13335, 172.64.33.216 AS13335, 173.245.59.216 AS13335, 2606:4700:58::adf5:3bd8 AS13335, 2803:f800:50::6ca2:c1d8 AS13335, 2a06:98c1:50::ac40:21d8 AS13335
ulla.ns.cloudflare.com 108.162.192.233 AS13335, 172.64.32.233 AS13335, 173.245.58.233 AS13335, 2606:4700:50::adf5:3ae9 AS13335, 2803:f800:50::6ca2:c0e9 AS13335, 2a06:98c1:50::ac40:20e9 AS13335
4security.dkbrynne.ns.cloudflare.com 108.162.194.65 AS13335, 162.159.38.65 AS13335, 172.64.34.65 AS13335, 2606:4700:50::a29f:2641 AS13335, 2803:f800:50::6ca2:c241 AS13335, 2a06:98c1:50::ac40:2241 AS13335
woz.ns.cloudflare.com 108.162.193.150 AS13335, 172.64.33.150 AS13335, 173.245.59.150 AS13335, 2606:4700:58::adf5:3b96 AS13335, 2803:f800:50::6ca2:c196 AS13335, 2a06:98c1:50::ac40:2196 AS13335
4see.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
4servicehotell.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
4shape.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
4site.dkns1.siteground.net 75.2.77.104 AS16509
ns2.siteground.net 99.83.229.113 AS16509
4smokers.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
4sound.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
4spaces.dkns-cloud-b1.googledomains.com 2001:4860:4802:32::6b AS15169, 216.239.32.107 AS15169
ns-cloud-b2.googledomains.com 2001:4860:4802:34::6b AS15169, 216.239.34.107 AS15169
ns-cloud-b3.googledomains.com 2001:4860:4802:36::6b AS15169, 216.239.36.107 AS15169
ns-cloud-b4.googledomains.com 2001:4860:4802:38::6b AS15169, 216.239.38.107 AS15169
4sport.dkclint.ns.cloudflare.com 108.162.193.90 AS13335, 172.64.33.90 AS13335, 173.245.59.90 AS13335, 2606:4700:58::adf5:3b5a AS13335, 2803:f800:50::6ca2:c15a AS13335, 2a06:98c1:50::ac40:215a AS13335
elisabeth.ns.cloudflare.com 108.162.194.224 AS13335, 162.159.38.224 AS13335, 172.64.34.224 AS13335, 2606:4700:50::a29f:26e0 AS13335, 2803:f800:50::6ca2:c2e0 AS13335, 2a06:98c1:50::ac40:22e0 AS13335
4ss.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
4strings.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
4sure.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
4syd.dkns1.arrownet.dk 62.61.130.2 AS15516
ns2.arrownet.dk 62.61.131.2 AS15516
4t.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
4tallet.dkmartin.ns.cloudflare.com 108.162.195.87 AS13335, 162.159.44.87 AS13335, 172.64.35.87 AS13335, 2606:4700:58::a29f:2c57 AS13335, 2803:f800:50::6ca2:c357 AS13335, 2a06:98c1:50::ac40:2357 AS13335
zainab.ns.cloudflare.com 108.162.194.149 AS13335, 162.159.38.149 AS13335, 172.64.34.149 AS13335, 2606:4700:50::a29f:2695 AS13335, 2803:f800:50::6ca2:c295 AS13335, 2a06:98c1:50::ac40:2295 AS13335
4teams.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
4tec.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
4theculture.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
4theweb.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
4thflooroffice.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
4thomsen.dkjustin.ns.cloudflare.com 108.162.193.187 AS13335, 172.64.33.187 AS13335, 173.245.59.187 AS13335, 2606:4700:58::adf5:3bbb AS13335, 2803:f800:50::6ca2:c1bb AS13335, 2a06:98c1:50::ac40:21bb AS13335
marjory.ns.cloudflare.com 108.162.192.193 AS13335, 172.64.32.193 AS13335, 173.245.58.193 AS13335, 2606:4700:50::adf5:3ac1 AS13335, 2803:f800:50::6ca2:c0c1 AS13335, 2a06:98c1:50::ac40:20c1 AS13335
4thway.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
4til1planet.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
4tilvenstre.dkdom.ns.cloudflare.com 108.162.193.157 AS13335, 172.64.33.157 AS13335, 173.245.59.157 AS13335, 2606:4700:58::adf5:3b9d AS13335, 2803:f800:50::6ca2:c19d AS13335, 2a06:98c1:50::ac40:219d AS13335
nola.ns.cloudflare.com 108.162.192.212 AS13335, 172.64.32.212 AS13335, 173.245.58.212 AS13335, 2606:4700:50::adf5:3ad4 AS13335, 2803:f800:50::6ca2:c0d4 AS13335, 2a06:98c1:50::ac40:20d4 AS13335
4timersarbejdsuge.dkgeorge.ns.cloudflare.com 108.162.193.167 AS13335, 172.64.33.167 AS13335, 173.245.59.167 AS13335, 2606:4700:58::adf5:3ba7 AS13335, 2803:f800:50::6ca2:c1a7 AS13335, 2a06:98c1:50::ac40:21a7 AS13335
heather.ns.cloudflare.com 108.162.192.161 AS13335, 172.64.32.161 AS13335, 173.245.58.161 AS13335, 2606:4700:50::adf5:3aa1 AS13335, 2803:f800:50::6ca2:c0a1 AS13335, 2a06:98c1:50::ac40:20a1 AS13335
4tinet.dkanton.ns.cloudflare.com 108.162.195.175 AS13335, 162.159.44.175 AS13335, 172.64.35.175 AS13335, 2606:4700:58::a29f:2caf AS13335, 2803:f800:50::6ca2:c3af AS13335, 2a06:98c1:50::ac40:23af AS13335
sofia.ns.cloudflare.com 108.162.192.223 AS13335, 172.64.32.223 AS13335, 173.245.58.223 AS13335, 2606:4700:50::adf5:3adf AS13335, 2803:f800:50::6ca2:c0df AS13335, 2a06:98c1:50::ac40:20df AS13335
4tools.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
4tun.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
4turbo.dkparking1.ovh.net 54.37.126.92 AS16276
parking2.ovh.net 54.37.126.93 AS16276
4tw.dkheidi.ns.cloudflare.com 108.162.194.236 AS13335, 162.159.38.236 AS13335, 172.64.34.236 AS13335, 2606:4700:50::a29f:26ec AS13335, 2803:f800:50::6ca2:c2ec AS13335, 2a06:98c1:50::ac40:22ec AS13335
nick.ns.cloudflare.com 108.162.193.213 AS13335, 172.64.33.213 AS13335, 173.245.59.213 AS13335, 2606:4700:58::adf5:3bd5 AS13335, 2803:f800:50::6ca2:c1d5 AS13335, 2a06:98c1:50::ac40:21d5 AS13335
4uall.dkns.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
4ubyg.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
4uconsulting.dkns1.dns-parking.com 162.159.24.201 AS13335, 2400:cb00:2049:1::a29f:18c9 AS13335
ns2.dns-parking.com 162.159.25.42 AS13335, 2400:cb00:2049:1::a29f:192a AS13335
4uentreprise.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
4ugo.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
4uhome.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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