🛡️ 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-chain.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-choice.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-class.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-club.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-collection.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
a-comfort.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-company.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-con.dkb7844972.online-server.cloud 82.165.189.144 AS8560
a-connect.dkmeilani.ns.cloudflare.com 108.162.194.196 AS13335, 162.159.38.196 AS13335, 172.64.34.196 AS13335, 2606:4700:50::a29f:26c4 AS13335, 2803:f800:50::6ca2:c2c4 AS13335, 2a06:98c1:50::ac40:22c4 AS13335
olof.ns.cloudflare.com 108.162.195.51 AS13335, 162.159.44.51 AS13335, 172.64.35.51 AS13335, 2606:4700:58::a29f:2c33 AS13335, 2803:f800:50::6ca2:c333 AS13335, 2a06:98c1:50::ac40:2333 AS13335
a-construction.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-consult.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-creative.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-d-c.dkns1.digitalocean.com 172.64.52.210 AS13335, 2606:4700:52::ac40:34d2 AS13335
ns2.digitalocean.com 172.64.53.21 AS13335, 2606:4700:5a::ac40:3515 AS13335
ns3.digitalocean.com 172.64.49.209 AS13335, 2606:4700:52::ac40:31d1 AS13335
a-d-p.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-dahl.dkagustin.ns.cloudflare.com 108.162.195.90 AS13335, 162.159.44.90 AS13335, 172.64.35.90 AS13335, 2606:4700:58::a29f:2c5a AS13335, 2803:f800:50::6ca2:c35a AS13335, 2a06:98c1:50::ac40:235a AS13335
lia.ns.cloudflare.com 108.162.192.185 AS13335, 172.64.32.185 AS13335, 173.245.58.185 AS13335, 2606:4700:50::adf5:3ab9 AS13335, 2803:f800:50::6ca2:c0b9 AS13335, 2a06:98c1:50::ac40:20b9 AS13335
a-damgaard.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-dan.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-data.dkjohnathan.ns.cloudflare.com 108.162.195.44 AS13335, 162.159.44.44 AS13335, 172.64.35.44 AS13335, 2606:4700:58::a29f:2c2c AS13335, 2803:f800:50::6ca2:c32c AS13335, 2a06:98c1:50::ac40:232c AS13335
ruth.ns.cloudflare.com 108.162.192.143 AS13335, 172.64.32.143 AS13335, 173.245.58.143 AS13335, 2606:4700:50::adf5:3a8f AS13335, 2803:f800:50::6ca2:c08f AS13335, 2a06:98c1:50::ac40:208f AS13335
a-deal.dkjihoon.ns.cloudflare.com 108.162.195.233 AS13335, 162.159.44.233 AS13335, 172.64.35.233 AS13335, 2606:4700:58::a29f:2ce9 AS13335, 2803:f800:50::6ca2:c3e9 AS13335, 2a06:98c1:50::ac40:23e9 AS13335
june.ns.cloudflare.com 108.162.192.176 AS13335, 172.64.32.176 AS13335, 173.245.58.176 AS13335, 2606:4700:50::adf5:3ab0 AS13335, 2803:f800:50::6ca2:c0b0 AS13335, 2a06:98c1:50::ac40:20b0 AS13335
a-dekoration.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-den.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-derma.dkns1.safebrands.fr 193.227.117.17 AS1921, 2a04:2b00:14cc::17 AS1921
ns2.safebrands.eu 194.50.187.18 AS1921, 2a04:2b00:14dd::18 AS1921
ns3.safebrands.com 194.0.182.19 AS1921, 2a04:2b00:14ee::19 AS1921
ns4.safebrands.org 193.227.117.20 AS1921, 2a04:2b00:14cc::20 AS1921
ns5.safebrands.tech 194.50.187.21 AS1921, 2a04:2b00:14dd::21 AS1921
a-design.dkns0.wixdns.net 216.239.32.101 AS15169
ns1.wixdns.net 216.239.34.101 AS15169
a-dpo.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-dragoer.dklamar.ns.cloudflare.com 108.162.195.142 AS13335, 162.159.44.142 AS13335, 172.64.35.142 AS13335, 2606:4700:58::a29f:2c8e AS13335, 2803:f800:50::6ca2:c38e AS13335, 2a06:98c1:50::ac40:238e AS13335
meg.ns.cloudflare.com 108.162.192.196 AS13335, 172.64.32.196 AS13335, 173.245.58.196 AS13335, 2606:4700:50::adf5:3ac4 AS13335, 2803:f800:50::6ca2:c0c4 AS13335, 2a06:98c1:50::ac40:20c4 AS13335
a-e-s.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-e.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-ef.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-effektivrengøring.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-el-teknik.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-el.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-elevator.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-enemark.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-eng.dkbruce.ns.cloudflare.com 108.162.193.77 AS13335, 172.64.33.77 AS13335, 173.245.59.77 AS13335, 2606:4700:58::adf5:3b4d AS13335, 2803:f800:50::6ca2:c14d AS13335, 2a06:98c1:50::ac40:214d AS13335
etta.ns.cloudflare.com 108.162.192.156 AS13335, 172.64.32.156 AS13335, 173.245.58.156 AS13335, 2606:4700:50::adf5:3a9c AS13335, 2803:f800:50::6ca2:c09c AS13335, 2a06:98c1:50::ac40:209c AS13335
a-entreprise.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-event.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-f-r.dkns1-09.azure-dns.com 13.107.236.9 AS8075, 2603:1061:0:700::9 AS8075
ns2-09.azure-dns.net 150.171.21.9 AS8075, 2620:1ec:8ec:700::9 AS8075
ns3-09.azure-dns.org 204.14.183.9 AS8075, 2a01:111:4000:700::9 AS8075
ns4-09.azure-dns.info 208.84.5.9 AS8075, 2620:1ec:bda:700::9 AS8075
a-factory.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-few.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-film.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-finans.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-flensborg.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-flis-shop.dkns4.wixdns.net 216.239.36.101 AS15169
ns5.wixdns.net 216.239.38.101 AS15169
a-flis.dkns4.wixdns.net 216.239.36.101 AS15169
ns5.wixdns.net 216.239.38.101 AS15169
a-flisshop.dkns4.wixdns.net 216.239.36.101 AS15169
ns5.wixdns.net 216.239.38.101 AS15169
a-flyt.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
a-forsberg.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-fotograf.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-friend.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-friis.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
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