🛡️ 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
1shops.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
1skud.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
1sky.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
1sl.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
1smile.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
1smykke.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
1sommerdag.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
1space.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
1spand.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
1spot.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
1st-choice.dkdaniella.ns.cloudflare.com 108.162.194.228 AS13335, 162.159.38.228 AS13335, 172.64.34.228 AS13335, 2606:4700:50::a29f:26e4 AS13335, 2803:f800:50::6ca2:c2e4 AS13335, 2a06:98c1:50::ac40:22e4 AS13335
grant.ns.cloudflare.com 108.162.195.130 AS13335, 162.159.44.130 AS13335, 172.64.35.130 AS13335, 2606:4700:58::a29f:2c82 AS13335, 2803:f800:50::6ca2:c382 AS13335, 2a06:98c1:50::ac40:2382 AS13335
1st-retail.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
1st-shot.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
1st-trading.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
1stantivirus.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
1stav.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
1stbackup.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
1stbox.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
1stcare.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
1stchoice.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
1stchoicebreeder.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
1stchoicebreedershop.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
1stchoicecharlottenlund.dkns1.takeaway.com 34.243.4.145 AS16509
ns2.takeaway.com 34.240.253.132 AS16509
1stclass.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
1stclassvinduespolering.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
1stcopenhagen.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
1stdev.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
1stdibs.dkns-1003.awsdns-61.net 205.251.195.235 AS16509, 2600:9000:5303:eb00::1 AS16509
ns-125.awsdns-15.com 205.251.192.125 AS16509, 2600:9000:5300:7d00::1 AS16509
ns-1306.awsdns-35.org 205.251.197.26 AS16509, 2600:9000:5305:1a00::1 AS16509
ns-1849.awsdns-39.co.uk 205.251.199.57 AS16509, 2600:9000:5307:3900::1 AS16509
1stdownphoto.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
1stdriver.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
1ste.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
1sted.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
1stehjaelp.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
1stehjælp.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
1stein.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
1stenergy.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
1step.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
1stepahead.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
1stepconsulting.dkns.dns-service.dk 77.247.76.118 AS31590
ns3.dns-service.dk 77.247.76.121 AS31590
1stepmarketing.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
1stepup.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
1stfirst.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
1stfloor.dkns1.parkingcrew.net 13.248.158.159 AS16509
ns2.parkingcrew.net 76.223.21.9 AS16509
1stflooryoga.dkns12.wixdns.net 216.239.36.101 AS15169
ns13.wixdns.net 216.239.38.101 AS15169
1sthost.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
1sthostedexchange.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
1sthosting.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
1stk-reklame.dkns1.mono.net 185.58.212.1 AS201595
ns2.mono.net 185.130.160.1 AS201595
ns3.mono.net 185.130.160.2 AS201595
ns4.mono.net 185.58.212.2 AS201595
1stkonsulent.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
1stlearning.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
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