🛡️ 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

1,182,584 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 address1,3040.11%Several NS names, but they all resolve to one IP, so they are really one server.
One IPv4 /24 and no IPv610,6830.90%All nameservers share one network: a routing problem there takes them all down.
One autonomous system757,07664.0%Common and usually fine with a large provider, but one network outage still takes all nameservers down.
No IPv6 nameserver85,2097.2%IPv6-only resolvers cannot reach the zone.

Click a row to list its domains (computed 2026-10-03 04:10).

📋 One autonomous system

757,076 domains
DomainNameservers and addresses
a-sønderborg.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
a-t.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
a-tag.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
a-talk.dkns1.nhl-data.dk 185.136.96.11 AS203391, 2a06:fb00:1::1:11 AS203391
ns2.nhl-data.dk 185.136.97.11 AS203391, 2a06:fb00:1::2:11 AS203391
ns3.nhl-data.dk 185.136.98.11 AS203391, 2a06:fb00:1::3:11 AS203391
ns4.nhl-data.dk 185.136.99.11 AS203391, 2a06:fb00:1::4:11 AS203391
a-taulborg.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
a-team-design.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
a-team.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
a-teamdesign.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
a-teams.dkns1.dnsserver.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.dnsserver.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
a-tec.dkns1.dnsserver.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.dnsserver.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
a-tech.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
a-technic.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
a-tegn.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
a-telte.dkelisabeth.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
gannon.ns.cloudflare.com 108.162.195.59 AS13335, 162.159.44.59 AS13335, 172.64.35.59 AS13335, 2606:4700:58::a29f:2c3b AS13335, 2803:f800:50::6ca2:c33b AS13335, 2a06:98c1:50::ac40:233b AS13335
a-tex.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
a-thompson.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
a-thorsteinsson.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
a-thorup.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
a-til.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
a-tjek.dkns1.curanet.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123
ns2.curanet.dk 2a02:2339:1:10f::123:123, 91.197.248.75
a-tjoernely.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
a-toget.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
a-trafik.dkns8.wixdns.net 216.239.32.101 AS15169
ns9.wixdns.net 216.239.34.101 AS15169
a-transport.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
a-typisk.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
a-ullerup.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
a-upholstery.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
a-v-e.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
a-vaabengaard.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
a-vang.dkkallie.ns.cloudflare.com 108.162.194.85 AS13335, 162.159.38.85 AS13335, 172.64.34.85 AS13335, 2606:4700:50::a29f:2655 AS13335, 2803:f800:50::6ca2:c255 AS13335, 2a06:98c1:50::ac40:2255 AS13335
kianchau.ns.cloudflare.com 108.162.195.179 AS13335, 162.159.44.179 AS13335, 172.64.35.179 AS13335, 2606:4700:58::a29f:2cb3 AS13335, 2803:f800:50::6ca2:c3b3 AS13335, 2a06:98c1:50::ac40:23b3 AS13335
a-varmepumper.dkjoan.ns.cloudflare.com 108.162.192.173 AS13335, 172.64.32.173 AS13335, 173.245.58.173 AS13335, 2606:4700:50::adf5:3aad AS13335, 2803:f800:50::6ca2:c0ad AS13335, 2a06:98c1:50::ac40:20ad AS13335
lloyd.ns.cloudflare.com 108.162.193.197 AS13335, 172.64.33.197 AS13335, 173.245.59.197 AS13335, 2606:4700:58::adf5:3bc5 AS13335, 2803:f800:50::6ca2:c1c5 AS13335, 2a06:98c1:50::ac40:21c5 AS13335
a-varmeservice.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
a-vask.dksuzanne.ns.cloudflare.com 108.162.194.87 AS13335, 162.159.38.87 AS13335, 172.64.34.87 AS13335, 2606:4700:50::a29f:2657 AS13335, 2803:f800:50::6ca2:c257 AS13335, 2a06:98c1:50::ac40:2257 AS13335
yew.ns.cloudflare.com 108.162.195.80 AS13335, 162.159.44.80 AS13335, 172.64.35.80 AS13335, 2606:4700:58::a29f:2c50 AS13335, 2803:f800:50::6ca2:c350 AS13335, 2a06:98c1:50::ac40:2350 AS13335
a-venue.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
a-view.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
a-vinstouw.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
a-vis.dkns1.jth.net 212.237.178.27 AS204151, 2a06:4005:8003::2 AS204151
ns4.jth.net 2a06:4004:b026::1 AS204151, 87.104.241.106 AS204151
a-vvs.dkns1.gnrx.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.gnrx.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
a-w-a.dkali.ns.cloudflare.com 108.162.192.59 AS13335, 172.64.32.59 AS13335, 173.245.58.59 AS13335, 2606:4700:50::adf5:3a3b AS13335, 2803:f800:50::6ca2:c03b AS13335, 2a06:98c1:50::ac40:203b AS13335
steven.ns.cloudflare.com 108.162.195.17 AS13335, 162.159.44.17 AS13335, 172.64.35.17 AS13335, 2606:4700:58::a29f:2c11 AS13335, 2803:f800:50::6ca2:c311 AS13335, 2a06:98c1:50::ac40:2311 AS13335
a-ware.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
a-way.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
a-wear.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
a-web.dkmary.ns.cloudflare.com 108.162.192.134 AS13335, 172.64.32.134 AS13335, 173.245.58.134 AS13335, 2606:4700:50::adf5:3a86 AS13335, 2803:f800:50::6ca2:c086 AS13335, 2a06:98c1:50::ac40:2086 AS13335
steven.ns.cloudflare.com 108.162.195.17 AS13335, 162.159.44.17 AS13335, 172.64.35.17 AS13335, 2606:4700:58::a29f:2c11 AS13335, 2803:f800:50::6ca2:c311 AS13335, 2a06:98c1:50::ac40:2311 AS13335
a-web2b.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
a-weber.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
a-website.dkdavina.ns.cloudflare.com 108.162.194.40 AS13335, 162.159.38.40 AS13335, 172.64.34.40 AS13335, 2606:4700:50::a29f:2628 AS13335, 2803:f800:50::6ca2:c228 AS13335, 2a06:98c1:50::ac40:2228 AS13335
nitin.ns.cloudflare.com 108.162.193.215 AS13335, 172.64.33.215 AS13335, 173.245.59.215 AS13335, 2606:4700:58::adf5:3bd7 AS13335, 2803:f800:50::6ca2:c1d7 AS13335, 2a06:98c1:50::ac40:21d7 AS13335
a-winther.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
a-wrap.dkachiel.ns.cloudflare.com 108.162.195.123 AS13335, 162.159.44.123 AS13335, 172.64.35.123 AS13335, 2606:4700:58::a29f:2c7b AS13335, 2803:f800:50::6ca2:c37b AS13335, 2a06:98c1:50::ac40:237b 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
a-z-bogholderi.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
a-z-trading.dkns1.dnsserver.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.dnsserver.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
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