🛡️ 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
zth.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
ztilleto.dkalla.ns.cloudflare.com 108.162.192.62 AS13335, 172.64.32.62 AS13335, 173.245.58.62 AS13335, 2606:4700:50::adf5:3a3e AS13335, 2803:f800:50::6ca2:c03e AS13335, 2a06:98c1:50::ac40:203e AS13335
howard.ns.cloudflare.com 108.162.195.171 AS13335, 162.159.44.171 AS13335, 172.64.35.171 AS13335, 2606:4700:58::a29f:2cab AS13335, 2803:f800:50::6ca2:c3ab AS13335, 2a06:98c1:50::ac40:23ab AS13335
ztn.dkdee.ns.cloudflare.com 108.162.192.93 AS13335, 172.64.32.93 AS13335, 173.245.58.93 AS13335, 2606:4700:50::adf5:3a5d AS13335, 2803:f800:50::6ca2:c05d AS13335, 2a06:98c1:50::ac40:205d AS13335
james.ns.cloudflare.com 108.162.193.178 AS13335, 172.64.33.178 AS13335, 173.245.59.178 AS13335, 2606:4700:58::adf5:3bb2 AS13335, 2803:f800:50::6ca2:c1b2 AS13335, 2a06:98c1:50::ac40:21b2 AS13335
ztna.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
zto100.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
ztoilets.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
ztorage.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
ztore.dklucy.ns.cloudflare.com 108.162.192.133 AS13335, 172.64.32.133 AS13335, 173.245.58.133 AS13335, 2606:4700:50::adf5:3a85 AS13335, 2803:f800:50::6ca2:c085 AS13335, 2a06:98c1:50::ac40:2085 AS13335
trevor.ns.cloudflare.com 108.162.195.154 AS13335, 162.159.44.154 AS13335, 172.64.35.154 AS13335, 2606:4700:58::a29f:2c9a AS13335, 2803:f800:50::6ca2:c39a AS13335, 2a06:98c1:50::ac40:239a AS13335
ztrong.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
ztructor.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
ztu.dkanita.ns.cloudflare.com 108.162.194.82 AS13335, 162.159.38.82 AS13335, 172.64.34.82 AS13335, 2606:4700:50::a29f:2652 AS13335, 2803:f800:50::6ca2:c252 AS13335, 2a06:98c1:50::ac40:2252 AS13335
fattouche.ns.cloudflare.com 108.162.195.48 AS13335, 162.159.44.48 AS13335, 172.64.35.48 AS13335, 2606:4700:58::a29f:2c30 AS13335, 2803:f800:50::6ca2:c330 AS13335, 2a06:98c1:50::ac40:2330 AS13335
zty.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
ztyres.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
zu-haveservice.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
zubardubar.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
zubbdigital.dkdave.ns.cloudflare.com 108.162.193.109 AS13335, 172.64.33.109 AS13335, 173.245.59.109 AS13335, 2606:4700:58::adf5:3b6d AS13335, 2803:f800:50::6ca2:c16d AS13335, 2a06:98c1:50::ac40:216d AS13335
jean.ns.cloudflare.com 108.162.192.121 AS13335, 172.64.32.121 AS13335, 173.245.58.121 AS13335, 2606:4700:50::adf5:3a79 AS13335, 2803:f800:50::6ca2:c079 AS13335, 2a06:98c1:50::ac40:2079 AS13335
zubizuri.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
zublin.dkns-1310.awsdns-35.org 205.251.197.30 AS16509, 2600:9000:5305:1e00::1 AS16509
ns-1738.awsdns-25.co.uk 205.251.198.202 AS16509, 2600:9000:5306:ca00::1 AS16509
ns-893.awsdns-47.net 205.251.195.125 AS16509, 2600:9000:5303:7d00::1 AS16509
ns-90.awsdns-11.com 205.251.192.90 AS16509, 2600:9000:5300:5a00::1 AS16509
zubsolv.dkdns1.comlaude-dns.com 198.51.44.11 AS62597, 2620:4d:4000:6259:7:11:0:1 AS62597
dns2.comlaude-dns.net 198.51.45.11 AS62597, 2a00:edc0:6259:7:11::2 AS62597
dns3.comlaude-dns.co.uk 198.51.44.75 AS62597, 2620:4d:4000:6259:7:11:0:3 AS62597
dns4.comlaude-dns.eu 198.51.45.75 AS62597, 2a00:edc0:6259:7:11::4 AS62597
zubstanz.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
zuca.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
zucce.dkhank.ns.cloudflare.com 108.162.193.116 AS13335, 172.64.33.116 AS13335, 173.245.59.116 AS13335, 2606:4700:58::adf5:3b74 AS13335, 2803:f800:50::6ca2:c174 AS13335, 2a06:98c1:50::ac40:2174 AS13335
love.ns.cloudflare.com 108.162.194.119 AS13335, 162.159.38.119 AS13335, 172.64.34.119 AS13335, 2606:4700:50::a29f:2677 AS13335, 2803:f800:50::6ca2:c277 AS13335, 2a06:98c1:50::ac40:2277 AS13335
zuccedesign.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
zucces.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
zucchini.dkns.wannafind.dk 185.25.141.6 AS48854, 2a02:2339:4006:103:1c:3f6d:daba:dee AS48854
ns2.wannafind.dk 2a02:2339:1:104::daba:daa AS48854, 91.197.248.69 AS48854
zudo.dkart.ns.cloudflare.com 108.162.193.102 AS13335, 172.64.33.102 AS13335, 173.245.59.102 AS13335, 2606:4700:58::adf5:3b66 AS13335, 2803:f800:50::6ca2:c166 AS13335, 2a06:98c1:50::ac40:2166 AS13335
irma.ns.cloudflare.com 108.162.192.166 AS13335, 172.64.32.166 AS13335, 173.245.58.166 AS13335, 2606:4700:50::adf5:3aa6 AS13335, 2803:f800:50::6ca2:c0a6 AS13335, 2a06:98c1:50::ac40:20a6 AS13335
zue.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
zueblin.dkns-1115.awsdns-11.org 205.251.196.91 AS16509, 2600:9000:5304:5b00::1 AS16509
ns-1815.awsdns-34.co.uk 205.251.199.23 AS16509, 2600:9000:5307:1700::1 AS16509
ns-394.awsdns-49.com 205.251.193.138 AS16509, 2600:9000:5301:8a00::1 AS16509
ns-859.awsdns-43.net 205.251.195.91 AS16509, 2600:9000:5303:5b00::1 AS16509
zuffenhausen.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
zuffenteile.dkdns100.ovh.net 2001:41d0:d00:fa00::2 AS16276, 5.135.250.177 AS16276
ns100.ovh.net 2001:41d0:b00:f400::2 AS16276, 5.135.44.185 AS16276
zugami.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
zugest.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
zuh.dkns1.regsj.dk 91.198.168.21 AS43806
ns2.regsj.dk 91.198.168.22 AS43806
zuhause.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
zuidberg.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
zuizui-berner.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
zukak.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
zuki.dkns3.webhot.dk 178.72.21.249 AS3342
ns4.webhot.dk 178.72.21.250 AS3342
zuko.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
zuku.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
zukunft-byg.dkns7.bricksite.net 35.246.226.10 AS396982
ns8.bricksite.net 35.242.190.82 AS396982
zukunft.dkauth31.ns.sonnit.dk 185.136.96.66 AS203391, 2a06:fb00:1::1:66 AS203391
auth32.ns.sonnit.dk 185.136.97.66 AS203391, 2a06:fb00:1::2:66 AS203391
auth33.ns.sonnit.dk 185.136.98.66 AS203391, 2a06:fb00:1::3:66 AS203391
auth34.ns.sonnit.dk 185.136.99.66 AS203391, 2a06:fb00:1::4:66 AS203391
zul.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
zulabet.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
zulakbh.dkamit.ns.cloudflare.com 108.162.193.63 AS13335, 172.64.33.63 AS13335, 173.245.59.63 AS13335, 2606:4700:58::adf5:3b3f AS13335, 2803:f800:50::6ca2:c13f AS13335, 2a06:98c1:50::ac40:213f AS13335
leah.ns.cloudflare.com 108.162.192.129 AS13335, 172.64.32.129 AS13335, 173.245.58.129 AS13335, 2606:4700:50::adf5:3a81 AS13335, 2803:f800:50::6ca2:c081 AS13335, 2a06:98c1:50::ac40:2081 AS13335
zulfo.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
zulfovski.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
zulily.dkdns1.idp365.net 162.159.27.131 AS13335, 2400:cb00:2049:1::a29f:1b83 AS13335
dns2.idp365.net 162.159.48.3 AS13335, 2400:cb00:2049:1::a29f:3003 AS13335
dns3.idp365.net 162.159.49.254 AS13335, 2400:cb00:2049:1::a29f:31fe AS13335
zuline.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
zulix.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
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