🛡️ 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

1,185,762 working delegations with resolvable nameservers (lame excluded)
Every nameserver is on…DomainsShareWhy it matters
A single nameserver host1480.01%Any outage or mistake on that host takes the domain offline; RFC 1034 asks for at least two.
A single nameserver address1,3100.11%Several NS names, but they all resolve to one IP, so they are really one server.
One IPv4 /24 and no IPv610,8150.91%All nameservers share one network: a routing problem there takes them all down.
One autonomous system754,61263.6%Common and usually fine with a large provider, but one network outage still takes all nameservers down.
No IPv6 nameserver86,0127.3%IPv6-only resolvers cannot reach the zone.

Click a row to list its domains (computed 2026-09-30 00:23).

📋 One autonomous system

754,612 domains
DomainNameservers and addresses
1bil.dkns1.vercel-dns.com 198.51.44.13 AS62597, 2620:4d:4000:6259:7:13:0:1 AS62597
ns2.vercel-dns.com 198.51.45.13 AS62597, 2a00:edc0:6259:7:13::2 AS62597
1birkerod.dkkarina.ns.cloudflare.com 108.162.192.178 AS13335, 172.64.32.178 AS13335, 173.245.58.178 AS13335, 2606:4700:50::adf5:3ab2 AS13335, 2803:f800:50::6ca2:c0b2 AS13335, 2a06:98c1:50::ac40:20b2 AS13335
kurt.ns.cloudflare.com 108.162.193.193 AS13335, 172.64.33.193 AS13335, 173.245.59.193 AS13335, 2606:4700:58::adf5:3bc1 AS13335, 2803:f800:50::6ca2:c1c1 AS13335, 2a06:98c1:50::ac40:21c1 AS13335
1birkeroed.dkkarina.ns.cloudflare.com 108.162.192.178 AS13335, 172.64.32.178 AS13335, 173.245.58.178 AS13335, 2606:4700:50::adf5:3ab2 AS13335, 2803:f800:50::6ca2:c0b2 AS13335, 2a06:98c1:50::ac40:20b2 AS13335
kurt.ns.cloudflare.com 108.162.193.193 AS13335, 172.64.33.193 AS13335, 173.245.59.193 AS13335, 2606:4700:58::adf5:3bc1 AS13335, 2803:f800:50::6ca2:c1c1 AS13335, 2a06:98c1:50::ac40:21c1 AS13335
1birkerød.dkkarina.ns.cloudflare.com 108.162.192.178 AS13335, 172.64.32.178 AS13335, 173.245.58.178 AS13335, 2606:4700:50::adf5:3ab2 AS13335, 2803:f800:50::6ca2:c0b2 AS13335, 2a06:98c1:50::ac40:20b2 AS13335
kurt.ns.cloudflare.com 108.162.193.193 AS13335, 172.64.33.193 AS13335, 173.245.59.193 AS13335, 2606:4700:58::adf5:3bc1 AS13335, 2803:f800:50::6ca2:c1c1 AS13335, 2a06:98c1:50::ac40:21c1 AS13335
1box.dkns1.nordicway.dk 2a01:4f8:1c1a:a1e7::1 AS24940, 91.98.140.195 AS24940
ns2.nordicway.dk 2a01:4f8:c012:4db6::1 AS24940, 49.13.80.249 AS24940
ns3.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
1box2smile.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
1bureau.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
1c.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
1c5.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
1c5konsulent.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
1car.dkns1.wwi.dk 208.94.148.4 AS16552, 2600:1800:10::1 AS16552
ns2.wwi.dk 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
1cb.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
1cc.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
1cetera.dkns1.siteground.net 75.2.77.104 AS16509
ns2.siteground.net 99.83.229.113 AS16509
1chat.dkns-1103.awsdns-09.org 205.251.196.79 AS16509, 2600:9000:5304:4f00::1 AS16509
ns-1628.awsdns-11.co.uk 205.251.198.92 AS16509, 2600:9000:5306:5c00::1 AS16509
ns-90.awsdns-11.com 205.251.192.90 AS16509, 2600:9000:5300:5a00::1 AS16509
ns-990.awsdns-59.net 205.251.195.222 AS16509, 2600:9000:5303:de00::1 AS16509
1click.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
1cms.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
1code.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
1community.dkns-1467.awsdns-55.org 205.251.197.187 AS16509, 2600:9000:5305:bb00::1 AS16509
ns-1542.awsdns-00.co.uk 205.251.198.6 AS16509, 2600:9000:5306:600::1 AS16509
ns-536.awsdns-03.net 205.251.194.24 AS16509, 2600:9000:5302:1800::1 AS16509
ns-94.awsdns-11.com 205.251.192.94 AS16509, 2600:9000:5300:5e00::1 AS16509
1cover.dkdns1.safenames.com 162.159.48.132 AS13335, 2400:cb00:2049:1::a29f:3084 AS13335
dns2.safenames.net 162.159.49.170 AS13335, 2400:cb00:2049:1::a29f:31aa AS13335
dns3.safenames.org 172.64.48.23 AS13335, 2400:cb00:2049:1::ac40:3017 AS13335
1crm.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
1d10t.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
1d1d.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
1dags.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
1dayweb.dkjack.ns.cloudflare.com 108.162.193.121 AS13335, 172.64.33.121 AS13335, 173.245.59.121 AS13335, 2606:4700:58::adf5:3b79 AS13335, 2803:f800:50::6ca2:c179 AS13335, 2a06:98c1:50::ac40:2179 AS13335
kristin.ns.cloudflare.com 108.162.192.181 AS13335, 172.64.32.181 AS13335, 173.245.58.181 AS13335, 2606:4700:50::adf5:3ab5 AS13335, 2803:f800:50::6ca2:c0b5 AS13335, 2a06:98c1:50::ac40:20b5 AS13335
1demo.dkns1.siteground.net 75.2.77.104 AS16509
ns2.siteground.net 99.83.229.113 AS16509
1depot.dkns3.hostworld.dk 217.160.222.205 AS8560, 2a02:247a:256:2c00:1::1 AS8560
ns4.hostworld.dk 217.160.220.14 AS8560, 2a02:247a:256:2c00::1 AS8560
1depotrum.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
1digital.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
1dir.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
1direction.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
1division.dkbeth.ns.cloudflare.com 108.162.192.103 AS13335, 172.64.32.103 AS13335, 173.245.58.103 AS13335, 2606:4700:50::adf5:3a67 AS13335, 2803:f800:50::6ca2:c067 AS13335, 2a06:98c1:50::ac40:2067 AS13335
jim.ns.cloudflare.com 108.162.193.125 AS13335, 172.64.33.125 AS13335, 173.245.59.125 AS13335, 2606:4700:58::adf5:3b7d AS13335, 2803:f800:50::6ca2:c17d AS13335, 2a06:98c1:50::ac40:217d AS13335
1dk.dkdawn.ns.cloudflare.com 108.162.192.106 AS13335, 172.64.32.106 AS13335, 173.245.58.106 AS13335, 2606:4700:50::adf5:3a6a AS13335, 2803:f800:50::6ca2:c06a AS13335, 2a06:98c1:50::ac40:206a AS13335
will.ns.cloudflare.com 108.162.193.149 AS13335, 172.64.33.149 AS13335, 173.245.59.149 AS13335, 2606:4700:58::adf5:3b95 AS13335, 2803:f800:50::6ca2:c195 AS13335, 2a06:98c1:50::ac40:2195 AS13335
1donation.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
1drive.dkns1-06.azure-dns.com 13.107.236.6 AS8075, 2603:1061:0:700::6 AS8075
ns2-06.azure-dns.net 150.171.21.6 AS8075, 2620:1ec:8ec:700::6 AS8075
ns3-06.azure-dns.org 204.14.183.6 AS8075, 2a01:111:4000:700::6 AS8075
ns4-06.azure-dns.info 208.84.5.6 AS8075, 2620:1ec:bda:700::6 AS8075
1driver.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
1e.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
1ejerbiler.dkns1.abovedomains.com 103.224.182.77 AS133618, 103.224.182.85 AS133618, 103.224.182.9 AS133618, 103.224.212.9 AS133618
ns2.abovedomains.com 103.224.182.10 AS133618, 103.224.212.10 AS133618, 103.224.212.51 AS133618, 103.224.212.53 AS133618
1ekstra.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
1ekstramand.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
1elektriker.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
1email.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
1en.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
1enkelt.dkdns1.p01.nsone.net 198.51.44.1 AS62597, 2620:4d:4000:6259:7:1:0:1 AS62597
dns2.p01.nsone.net 198.51.45.1 AS62597, 2a00:edc0:6259:7:1::2 AS62597
dns3.p01.nsone.net 198.51.44.65 AS62597, 2620:4d:4000:6259:7:1:0:3 AS62597
dns4.p01.nsone.net 198.51.45.65 AS62597, 2a00:edc0:6259:7:1::4 AS62597
1entreprise.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
1er.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
1ergi.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
1ersen.dkns1.site4now.net 204.188.197.246 AS46844, 204.188.197.84 AS46844, 70.39.73.45 AS46844
ns2.site4now.net 208.98.36.41 AS46844, 45.58.159.232 AS46844, 45.58.159.233 AS46844
ns3.site4now.net 208.98.36.42 AS46844, 45.58.159.230 AS46844, 45.58.159.231 AS46844
1estate.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
1f.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
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