🛡️ 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

1,183,542 working delegations with resolvable nameservers (lame excluded)
Every nameserver is on…DomainsShareWhy it matters
A single nameserver host1470.01%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 IPv610,6770.90%All nameservers share one network: a routing problem there takes them all down.
One autonomous system758,00864.0%Common and usually fine with a large provider, but one network outage still takes all nameservers down.
No IPv6 nameserver85,4057.2%IPv6-only resolvers cannot reach the zone.

Click a row to list its domains (computed 2026-10-05 05:55).

📋 One autonomous system

758,008 domains
DomainNameservers and addresses
acmarkservice.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
acmassageterapi.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
acmatch.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
acmdesign.dkkayleigh.ns.cloudflare.com 108.162.194.92 AS13335, 162.159.38.92 AS13335, 172.64.34.92 AS13335, 2606:4700:50::a29f:265c AS13335, 2803:f800:50::6ca2:c25c AS13335, 2a06:98c1:50::ac40:225c AS13335
keenan.ns.cloudflare.com 108.162.195.11 AS13335, 162.159.44.11 AS13335, 172.64.35.11 AS13335, 2606:4700:58::a29f:2c0b AS13335, 2803:f800:50::6ca2:c30b AS13335, 2a06:98c1:50::ac40:230b AS13335
acmedia.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
acmf.dkns1.nhl-data.dk 185.136.96.11 AS203391, 2a06:fb00:1::1:11 AS203391
ns2.nhl-data.dk 185.136.97.11 AS203391, 2a06:fb00:1::2:11 AS203391
ns3.nhl-data.dk 185.136.98.11 AS203391, 2a06:fb00:1::3:11 AS203391
ns4.nhl-data.dk 185.136.99.11 AS203391, 2a06:fb00:1::4:11 AS203391
acmforvaltning.dkns1.nhl-data.dk 185.136.96.11 AS203391, 2a06:fb00:1::1:11 AS203391
ns2.nhl-data.dk 185.136.97.11 AS203391, 2a06:fb00:1::2:11 AS203391
ns3.nhl-data.dk 185.136.98.11 AS203391, 2a06:fb00:1::3:11 AS203391
ns4.nhl-data.dk 185.136.99.11 AS203391, 2a06:fb00:1::4:11 AS203391
acmfunds.dkamavn0201.acml.com 206.218.206.221 AS13821
amavn0202.acml.com 206.218.206.223 AS13821
lnhddns01.acml.com 206.218.234.20 AS13821
pscddns01.acml.com 206.218.214.20 AS13821
pscdvdns.acml.com 206.218.214.19 AS13821
pwyvn0101.acml.com 206.218.223.27 AS13821
pwyvn0301.acml.com 206.218.223.43 AS13821
acmilanfan.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
acmineralsgroup.dkns1.provalue.nl 212.61.68.67 AS8426, 2a02:830:1:2::68:67 AS8426
ns2.provalue.nl 212.61.69.67 AS8426, 2a02:830:1:2::69:67 AS8426
ns3.provalue.nl 212.61.69.167 AS8426, 2a02:830:1:2::69:167 AS8426
acmm.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
acmmediatech.dkns1.namesystem.se 195.238.76.18 AS42708, 2a02:750:aaaa::1 AS42708
ns2.namesystem.se 195.238.77.18 AS42708, 2a02:750:aaaa::2 AS42708
ns3.namesystem.se 195.20.206.18 AS42708, 2a02:750:aaaa::3 AS42708
acmn.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
acmobil.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
acmobil1.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
acmors.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
acmotorparts.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
acmotors.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
acmpartners.dkns12.wixdns.net 216.239.36.101 AS15169
ns13.wixdns.net 216.239.38.101 AS15169
acmycar.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
acn-vvs.dkpns31.cloudns.net 185.136.96.66 AS203391, 2a06:fb00:1::1:66 AS203391
pns32.cloudns.net 185.136.97.66 AS203391, 2a06:fb00:1::2:66 AS203391
pns33.cloudns.net 185.136.98.66 AS203391, 2a06:fb00:1::3:66 AS203391
pns34.cloudns.net 185.136.99.66 AS203391, 2a06:fb00:1::4:66 AS203391
acn.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
acnacalm.dkns-1486.awsdns-57.org 205.251.197.206 AS16509, 2600:9000:5305:ce00::1 AS16509
ns-1873.awsdns-42.co.uk 205.251.199.81 AS16509, 2600:9000:5307:5100::1 AS16509
ns-278.awsdns-34.com 205.251.193.22 AS16509, 2600:9000:5301:1600::1 AS16509
ns-662.awsdns-18.net 205.251.194.150 AS16509, 2600:9000:5302:9600::1 AS16509
acne.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
acnederby.dkcharles.ns.cloudflare.com 108.162.193.83 AS13335, 172.64.33.83 AS13335, 173.245.59.83 AS13335, 2606:4700:58::adf5:3b53 AS13335, 2803:f800:50::6ca2:c153 AS13335, 2a06:98c1:50::ac40:2153 AS13335
savanna.ns.cloudflare.com 108.162.194.136 AS13335, 162.159.38.136 AS13335, 172.64.34.136 AS13335, 2606:4700:50::a29f:2688 AS13335, 2803:f800:50::6ca2:c288 AS13335, 2a06:98c1:50::ac40:2288 AS13335
acneklinik.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
acneklinikken.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
acnespecialist.dkns1.parkingcrew.net 13.248.158.159 AS16509
ns2.parkingcrew.net 76.223.21.9 AS16509
acnet.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
acneuro.dkns1.softlayer.com 2607:f0d0:0:f:1::1 AS36351, 67.228.254.4 AS36351
ns2.softlayer.com 2607:f0d0:0:f:2::1 AS36351, 67.228.255.5 AS36351
acnextsolutions.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
acnhwa.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
acnielsen.dkedns64.ultradns.biz 204.74.67.64 AS12008, 2610:a1:1015::240 AS12008
edns64.ultradns.com 2001:502:f3ff::240 AS12008, 204.74.66.64 AS12008
edns64.ultradns.net 204.74.110.64 AS12008, 2610:a1:1014::240 AS12008
edns64.ultradns.org 2001:502:4612::240 AS12008, 204.74.111.64 AS12008
acnord.dkeve.ns.cloudflare.com 108.162.194.204 AS13335, 162.159.38.204 AS13335, 172.64.34.204 AS13335, 2606:4700:50::a29f:26cc AS13335, 2803:f800:50::6ca2:c2cc AS13335, 2a06:98c1:50::ac40:22cc AS13335
nicolas.ns.cloudflare.com 108.162.195.84 AS13335, 162.159.44.84 AS13335, 172.64.35.84 AS13335, 2606:4700:58::a29f:2c54 AS13335, 2803:f800:50::6ca2:c354 AS13335, 2a06:98c1:50::ac40:2354 AS13335
acnotech.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
acnovavista.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
acnsikring.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
aco-engineering.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
aco-plast.dkns10.dnsadmin.dk 208.94.148.4 AS16552, 2600:1800:10::1 AS16552
ns11.dns-admin.dk 208.80.124.4 AS16552, 2600:1801:11::1 AS16552
ns12.dnsadmin.dk 208.80.126.4 AS16552, 2600:1802:12::1 AS16552
ns13.dns-admin.dk 208.80.125.4 AS16552, 2600:1801:13::1 AS16552
ns14.dnsadmin.dk 208.80.127.4 AS16552, 2600:1802:14::1 AS16552
ns15.dns-admin.dk 208.94.149.4 AS16552, 2600:1800:15::1 AS16552
acoa.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
acoatselectet.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
acob.dkjustin.ns.cloudflare.com 108.162.193.187 AS13335, 172.64.33.187 AS13335, 173.245.59.187 AS13335, 2606:4700:58::adf5:3bbb AS13335, 2803:f800:50::6ca2:c1bb AS13335, 2a06:98c1:50::ac40:21bb AS13335
kallie.ns.cloudflare.com 108.162.194.85 AS13335, 162.159.38.85 AS13335, 172.64.34.85 AS13335, 2606:4700:50::a29f:2655 AS13335, 2803:f800:50::6ca2:c255 AS13335, 2a06:98c1:50::ac40:2255 AS13335
acobaps.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
acobs.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
acocomponents.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
acodewear.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
acodyne.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
acoform.dkns1.msvit.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.msvit.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
acoglobe.dkns1.shellhost.dk 193.200.90.91 AS62121, 2001:67c:564::13 AS62121
ns2.shellhost.dk 193.200.91.90 AS62121, 2001:67c:564::12 AS62121
acoindustrialcomponents.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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