🛡️ 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
østerberg.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
østerbjergegård.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
østerbjerregrav.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
østerbo-net.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
østerbrew.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
østerbro-begravelsesforretning.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
østerbro-bilhus.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
østerbro-if.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
østerbro-mediecenter.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
østerbro-pakkeshop.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
østerbro.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
østerbroavis.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
østerbrobasen.dkns.cohaesio.net 217.30.38.181 AS47292
ns2.cohaesio.net 217.30.38.27 AS47292
østerbrobegravelsesforretning.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
østerbrobyvandring.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
østerbrodans.dkns.locuples.com 208.94.148.4 AS16552, 2600:1800:10::1 AS16552
ns2.locuples.com 208.80.124.4 AS16552, 2600:1801:11::1 AS16552
ns3.wwi.as 208.80.126.4 AS16552, 2600:1802:12::1 AS16552
ns4.wwi.eu 208.80.125.4 AS16552, 2600:1801:13::1 AS16552
østerbroeleservice.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
østerbrofacelifting.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
østerbrofodterapi.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
østerbrofysioterapeut.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
østerbrofysioterapi.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
østerbrogade.dkns1.telanco.dk 84.246.245.104 AS34165
ns2.telanco.dk 84.246.247.29 AS34165
østerbrogades-dyrlæger.dkblair.ns.cloudflare.com 108.162.194.121 AS13335, 162.159.38.121 AS13335, 172.64.34.121 AS13335, 2606:4700:50::a29f:2679 AS13335, 2803:f800:50::6ca2:c279 AS13335, 2a06:98c1:50::ac40:2279 AS13335
frank.ns.cloudflare.com 108.162.193.166 AS13335, 172.64.33.166 AS13335, 173.245.59.166 AS13335, 2606:4700:58::adf5:3ba6 AS13335, 2803:f800:50::6ca2:c1a6 AS13335, 2a06:98c1:50::ac40:21a6 AS13335
østerbroglarmester.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
østerbroglarmestre.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
østerbrojagttegn.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
østerbrojazzklub.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
østerbroklip.dkdarwin.ns.cloudflare.com 108.162.193.151 AS13335, 172.64.33.151 AS13335, 173.245.59.151 AS13335, 2606:4700:58::adf5:3b97 AS13335, 2803:f800:50::6ca2:c197 AS13335, 2a06:98c1:50::ac40:2197 AS13335
nia.ns.cloudflare.com 108.162.192.210 AS13335, 172.64.32.210 AS13335, 173.245.58.210 AS13335, 2606:4700:50::adf5:3ad2 AS13335, 2803:f800:50::6ca2:c0d2 AS13335, 2a06:98c1:50::ac40:20d2 AS13335
østerbrolaase.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
østerbroliv.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
østerbrolåse.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
østerbrolægerne.dkgate.profdoc.dk 80.62.243.243 AS3292
ns.profdoc.dk 80.62.243.242 AS3292
østerbromusikskole.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
østerbronx.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
østerbrooptik.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
østerbropsykolog.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
østerbropsykologen.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
østerbroreumatologi.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
østerbros-boghandel.dkgerald.ns.cloudflare.com 108.162.193.168 AS13335, 172.64.33.168 AS13335, 173.245.59.168 AS13335, 2606:4700:58::adf5:3ba8 AS13335, 2803:f800:50::6ca2:c1a8 AS13335, 2a06:98c1:50::ac40:21a8 AS13335
lina.ns.cloudflare.com 108.162.192.187 AS13335, 172.64.32.187 AS13335, 173.245.58.187 AS13335, 2606:4700:50::adf5:3abb AS13335, 2803:f800:50::6ca2:c0bb AS13335, 2a06:98c1:50::ac40:20bb AS13335
østerbrosboghandel.dkgerald.ns.cloudflare.com 108.162.193.168 AS13335, 172.64.33.168 AS13335, 173.245.59.168 AS13335, 2606:4700:58::adf5:3ba8 AS13335, 2803:f800:50::6ca2:c1a8 AS13335, 2a06:98c1:50::ac40:21a8 AS13335
lina.ns.cloudflare.com 108.162.192.187 AS13335, 172.64.32.187 AS13335, 173.245.58.187 AS13335, 2606:4700:50::adf5:3abb AS13335, 2803:f800:50::6ca2:c0bb AS13335, 2a06:98c1:50::ac40:20bb AS13335
østerbroskrædder.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
østerbroskøjtehal.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
østerbrosmedie.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
østerbrosol.dkns5.private-nameserver.net 205.185.112.60 AS53667
ns6.private-nameserver.net 199.195.255.60 AS53667
østerbrosolcenter.dkns5.private-nameserver.net 205.185.112.60 AS53667
ns6.private-nameserver.net 199.195.255.60 AS53667
østerbrotandklinik.dkns1.123hotel.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.123hotel.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
østerbrotandlæge.dkbristol.ns.cloudflare.com 108.162.194.47 AS13335, 162.159.38.47 AS13335, 172.64.34.47 AS13335, 2606:4700:50::a29f:262f AS13335, 2803:f800:50::6ca2:c22f AS13335, 2a06:98c1:50::ac40:222f AS13335
chuck.ns.cloudflare.com 108.162.193.86 AS13335, 172.64.33.86 AS13335, 173.245.59.86 AS13335, 2606:4700:58::adf5:3b56 AS13335, 2803:f800:50::6ca2:c156 AS13335, 2a06:98c1:50::ac40:2156 AS13335
østerbrotandlægecenter.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
østerbrotandlægerne.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
østerbroteater.dkleland.ns.cloudflare.com 108.162.195.8 AS13335, 162.159.44.8 AS13335, 172.64.35.8 AS13335, 2606:4700:58::a29f:2c08 AS13335, 2803:f800:50::6ca2:c308 AS13335, 2a06:98c1:50::ac40:2308 AS13335
norah.ns.cloudflare.com 108.162.194.70 AS13335, 162.159.38.70 AS13335, 172.64.34.70 AS13335, 2606:4700:50::a29f:2646 AS13335, 2803:f800:50::6ca2:c246 AS13335, 2a06:98c1:50::ac40:2246 AS13335
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