🛡️ 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

1,183,573 working delegations with resolvable nameservers (lame excluded)
Every nameserver is on…DomainsShareWhy it matters
A single nameserver host1450.01%Any outage or mistake on that host takes the domain offline; RFC 1034 asks for at least two.
A single nameserver address1,3060.11%Several NS names, but they all resolve to one IP, so they are really one server.
One IPv4 /24 and no IPv610,6800.90%All nameservers share one network: a routing problem there takes them all down.
One autonomous system757,94464.0%Common and usually fine with a large provider, but one network outage still takes all nameservers down.
No IPv6 nameserver85,2767.2%IPv6-only resolvers cannot reach the zone.

Click a row to list its domains (computed 2026-10-05 18:29).

📋 One autonomous system

757,944 domains
DomainNameservers and addresses
adsfitness.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
adshel-plakat.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
adshel-poster.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
adshop.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
adshub.dknelly.ns.cloudflare.com 108.162.192.209 AS13335, 172.64.32.209 AS13335, 173.245.58.209 AS13335, 2606:4700:50::adf5:3ad1 AS13335, 2803:f800:50::6ca2:c0d1 AS13335, 2a06:98c1:50::ac40:20d1 AS13335
seamus.ns.cloudflare.com 108.162.195.184 AS13335, 162.159.44.184 AS13335, 172.64.35.184 AS13335, 2606:4700:58::a29f:2cb8 AS13335, 2803:f800:50::6ca2:c3b8 AS13335, 2a06:98c1:50::ac40:23b8 AS13335
adsign.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
adsigns.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
adsimonsen.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
adskil.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
adsl-aau.dkaspen.ns.cloudflare.com 108.162.194.109 AS13335, 162.159.38.109 AS13335, 172.64.34.109 AS13335, 2606:4700:50::a29f:266d AS13335, 2803:f800:50::6ca2:c26d AS13335, 2a06:98c1:50::ac40:226d AS13335
clayton.ns.cloudflare.com 108.162.195.226 AS13335, 162.159.44.226 AS13335, 172.64.35.226 AS13335, 2606:4700:58::a29f:2ce2 AS13335, 2803:f800:50::6ca2:c3e2 AS13335, 2a06:98c1:50::ac40:23e2 AS13335
adsl.dkns1.telenor.dk 2001:1580:0:1806::10 AS9158, 212.242.39.142 AS9158
ns2.telenor.dk 2001:1580:0:1206::10 AS9158, 212.242.39.166 AS9158
adslab.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
adslev.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
adslevby.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
adslevvandvaerk.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
adslhome.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
adslibrary.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
adsltips.dkandy.ns.cloudflare.com 108.162.193.101 AS13335, 172.64.33.101 AS13335, 173.245.59.101 AS13335, 2606:4700:58::adf5:3b65 AS13335, 2803:f800:50::6ca2:c165 AS13335, 2a06:98c1:50::ac40:2165 AS13335
kim.ns.cloudflare.com 108.162.192.126 AS13335, 172.64.32.126 AS13335, 173.245.58.126 AS13335, 2606:4700:50::adf5:3a7e AS13335, 2803:f800:50::6ca2:c07e AS13335, 2a06:98c1:50::ac40:207e AS13335
adsm.dkali.ns.cloudflare.com 108.162.192.59 AS13335, 172.64.32.59 AS13335, 173.245.58.59 AS13335, 2606:4700:50::adf5:3a3b AS13335, 2803:f800:50::6ca2:c03b AS13335, 2a06:98c1:50::ac40:203b AS13335
arturo.ns.cloudflare.com 108.162.195.216 AS13335, 162.159.44.216 AS13335, 172.64.35.216 AS13335, 2606:4700:58::a29f:2cd8 AS13335, 2803:f800:50::6ca2:c3d8 AS13335, 2a06:98c1:50::ac40:23d8 AS13335
adsman.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
adsmark.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
adsmate.dkpat.ns.cloudflare.com 108.162.192.139 AS13335, 172.64.32.139 AS13335, 173.245.58.139 AS13335, 2606:4700:50::adf5:3a8b AS13335, 2803:f800:50::6ca2:c08b AS13335, 2a06:98c1:50::ac40:208b AS13335
randy.ns.cloudflare.com 108.162.195.109 AS13335, 162.159.44.109 AS13335, 172.64.35.109 AS13335, 2606:4700:58::a29f:2c6d AS13335, 2803:f800:50::6ca2:c36d AS13335, 2a06:98c1:50::ac40:236d AS13335
adso.dkns.mielke.dk 2001:ba8:1f1:f040::53, 85.119.82.156 AS8943
ns1.mielke.dk 2001:ba8:1f1:f03e::53, 85.119.83.184
ns2.mielke.dk 2001:ba8:1f1:f098::53, 85.119.82.85
adsoft.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
adsolute.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
adsolutions.dkns1.parkingcrew.net 13.248.158.159 AS16509
ns2.parkingcrew.net 76.223.21.9 AS16509
adson.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
adsonline.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
adsontest.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
adspace.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
adspartner.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
adsper.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
adspice.dkns1.nordicnumber.com 91.198.138.46 AS51167
ns2.nordicnumber.com 91.198.138.47 AS51167
ns3.nordicnumber.com 213.136.93.70 AS51167
adsplus.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
adsprog.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
adsquid.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
adssify.dkns.zone.eu 217.146.66.65 AS49604
ns2.zone.ee 2a02:29e9:30:53::a AS49604, 85.234.242.32 AS49604
ns3.zonedata.net 2a02:29e9:20:53::a AS49604, 85.234.247.50 AS49604
adstec.dkns1.telekom.net 2003:180:a:1000::53 AS3320, 212.185.24.65 AS3320
pns.dtag.de 194.25.0.125 AS3320, 2003:40:8000::100 AS3320
adster.dkivan.ns.cloudflare.com 108.162.193.120 AS13335, 172.64.33.120 AS13335, 173.245.59.120 AS13335, 2606:4700:58::adf5:3b78 AS13335, 2803:f800:50::6ca2:c178 AS13335, 2a06:98c1:50::ac40:2178 AS13335
vera.ns.cloudflare.com 108.162.192.147 AS13335, 172.64.32.147 AS13335, 173.245.58.147 AS13335, 2606:4700:50::adf5:3a93 AS13335, 2803:f800:50::6ca2:c093 AS13335, 2a06:98c1:50::ac40:2093 AS13335
adstiafsted.dkns1.webro.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.webro.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
adstiladrin.dknsgbr.comlaude.co.uk 198.51.44.11 AS62597, 2620:4d:4000:6259:7:11:0:1 AS62597
nssui.comlaude.ch 198.51.45.11 AS62597, 2a00:edc0:6259:7:11::2 AS62597
nsusa.comlaude.net 198.51.44.75 AS62597, 2620:4d:4000:6259:7:11:0:3 AS62597
adstrea.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
adstudio.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
adsuite.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
adsupply.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
adswap.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
adswork.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
adsystem.dkns1.kei.pl 94.152.254.100 AS58321
ns2.kei.pl 94.152.255.100 AS58321
adtail.dkns-1113.awsdns-11.org 205.251.196.89 AS16509, 2600:9000:5304:5900::1 AS16509
ns-1963.awsdns-53.co.uk 205.251.199.171 AS16509, 2600:9000:5307:ab00::1 AS16509
ns-260.awsdns-32.com 205.251.193.4 AS16509, 2600:9000:5301:400::1 AS16509
ns-635.awsdns-15.net 205.251.194.123 AS16509, 2600:9000:5302:7b00::1 AS16509
adtc.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
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