🛡️ 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

1,183,339 working delegations with resolvable nameservers (lame excluded)
Every nameserver is on…DomainsShareWhy it matters
A single nameserver host1460.01%Any outage or mistake on that host takes the domain offline; RFC 1034 asks for at least two.
A single nameserver address1,3090.11%Several NS names, but they all resolve to one IP, so they are really one server.
One IPv4 /24 and no IPv610,6840.90%All nameservers share one network: a routing problem there takes them all down.
One autonomous system757,75064.0%Common and usually fine with a large provider, but one network outage still takes all nameservers down.
No IPv6 nameserver85,1697.2%IPv6-only resolvers cannot reach the zone.

Click a row to list its domains (computed 2026-10-06 00:32).

📋 One autonomous system

757,750 domains
DomainNameservers and addresses
agnuscastus.dkns-1041.awsdns-02.org 205.251.196.17 AS16509, 2600:9000:5304:1100::1 AS16509
ns-1583.awsdns-05.co.uk 205.251.198.47 AS16509, 2600:9000:5306:2f00::1 AS16509
ns-396.awsdns-49.com 205.251.193.140 AS16509, 2600:9000:5301:8c00::1 AS16509
ns-701.awsdns-23.net 205.251.194.189 AS16509, 2600:9000:5302:bd00::1 AS16509
agnvig.dkemely.ns.cloudflare.com 108.162.194.209 AS13335, 162.159.38.209 AS13335, 172.64.34.209 AS13335, 2606:4700:50::a29f:26d1 AS13335, 2803:f800:50::6ca2:c2d1 AS13335, 2a06:98c1:50::ac40:22d1 AS13335
leo.ns.cloudflare.com 108.162.195.241 AS13335, 162.159.44.241 AS13335, 172.64.35.241 AS13335, 2606:4700:58::a29f:2cf1 AS13335, 2803:f800:50::6ca2:c3f1 AS13335, 2a06:98c1:50::ac40:23f1 AS13335
ago.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
agoaps.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
agoda.dkedns2.ultradns.biz 204.74.67.2 AS12008, 2610:a1:1015::202 AS12008
edns2.ultradns.com 2001:502:f3ff::202 AS12008, 204.74.66.2 AS12008
edns2.ultradns.net 204.74.110.2 AS12008, 2610:a1:1014::202 AS12008
edns2.ultradns.org 2001:502:4612::202 AS12008, 204.74.111.2 AS12008
agodesign.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
agoe.dkns1.rsyd.dk 193.163.230.6 AS44328
ns2.rsyd.dk 193.163.227.5 AS44328
agofabrikken.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
agogoe.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
agonconsult.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
agoodbook.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
agoodcase.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
agoodchoice.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
agooddaytodiehard.dkns31.twdcns.com 107.20.239.90 AS14618
ns32.twdcns.net 184.72.240.107 AS14618
ns33.twdcns.org 75.101.129.92 AS14618
ns34.twdcns.co.uk 107.22.247.169 AS14618
agoodsale.dkpeaches.ns.cloudflare.com 108.162.194.239 AS13335, 162.159.38.239 AS13335, 172.64.34.239 AS13335, 2606:4700:50::a29f:26ef AS13335, 2803:f800:50::6ca2:c2ef AS13335, 2a06:98c1:50::ac40:22ef AS13335
steven.ns.cloudflare.com 108.162.195.17 AS13335, 162.159.44.17 AS13335, 172.64.35.17 AS13335, 2606:4700:58::a29f:2c11 AS13335, 2803:f800:50::6ca2:c311 AS13335, 2a06:98c1:50::ac40:2311 AS13335
agoodyear.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
agoons.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
agora.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
agorafoods.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
agoraomega.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
agorasonic.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
agorasourcing.dkns1.aveo.dk 185.25.141.12 AS48854, 2a02:2339:4006:108::123 AS48854
ns2.aveo.dk 2a02:2339:1:10f::123:123 AS48854, 91.197.248.75 AS48854
agoratopia.dkizabella.ns.cloudflare.com 108.162.194.46 AS13335, 162.159.38.46 AS13335, 172.64.34.46 AS13335, 2606:4700:50::a29f:262e AS13335, 2803:f800:50::6ca2:c22e AS13335, 2a06:98c1:50::ac40:222e AS13335
ken.ns.cloudflare.com 108.162.193.127 AS13335, 172.64.33.127 AS13335, 173.245.59.127 AS13335, 2606:4700:58::adf5:3b7f AS13335, 2803:f800:50::6ca2:c17f AS13335, 2a06:98c1:50::ac40:217f AS13335
agoro.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
agos.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
agostino.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
agotta.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
agoy.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
agp-teknik.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
agp-tomrer.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
agp-tømrer.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
agp.dkns1.seo-linuxpl.com 94.152.254.111 AS58321
ns2.seo-linuxpl.com 94.152.255.111 AS58321
agpalilik.dkns1.ku.dk 192.38.110.174 AS1835, 2001:878:1070:10::174 AS1835
ns2.ku.dk 192.38.110.190 AS1835, 2001:878:1070:11::190 AS1835
agpartners.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
agpdev.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
agpentreprise.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
agpilates.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
agplan.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
agpr.dkns1.bdm.microsoftonline.com 13.107.236.208 AS8075, 2603:1061:0:700::d0 AS8075
ns2.bdm.microsoftonline.com 150.171.21.208 AS8075, 2620:1ec:8ec:700::d0 AS8075
ns3.bdm.microsoftonline.com 204.14.183.208 AS8075, 2a01:111:4000:700::d0 AS8075
ns4.bdm.microsoftonline.com 208.84.5.208 AS8075, 2620:1ec:bda:700::d0 AS8075
agptømrer.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
agpuds.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
agq.dkmack.ns.cloudflare.com 108.162.195.37 AS13335, 162.159.44.37 AS13335, 172.64.35.37 AS13335, 2606:4700:58::a29f:2c25 AS13335, 2803:f800:50::6ca2:c325 AS13335, 2a06:98c1:50::ac40:2325 AS13335
michelle.ns.cloudflare.com 108.162.192.201 AS13335, 172.64.32.201 AS13335, 173.245.58.201 AS13335, 2606:4700:50::adf5:3ac9 AS13335, 2803:f800:50::6ca2:c0c9 AS13335, 2a06:98c1:50::ac40:20c9 AS13335
agr.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
agra.dkcarlos.ns.cloudflare.com 108.162.195.112 AS13335, 162.159.44.112 AS13335, 172.64.35.112 AS13335, 2606:4700:58::a29f:2c70 AS13335, 2803:f800:50::6ca2:c370 AS13335, 2a06:98c1:50::ac40:2370 AS13335
fatima.ns.cloudflare.com 108.162.194.188 AS13335, 162.159.38.188 AS13335, 172.64.34.188 AS13335, 2606:4700:50::a29f:26bc AS13335, 2803:f800:50::6ca2:c2bc AS13335, 2a06:98c1:50::ac40:22bc AS13335
agraasboll.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
agrafik.dkprimary.infoserv.dk 139.162.157.8 AS63949, 2a01:7e01::f03c:91ff:fe59:943d AS63949
secondary.infoserv.dk 139.162.227.162 AS63949, 2a01:7e00::f03c:92ff:fe07:7dc2 AS63949
agrainproducts.dkdemi.ns.cloudflare.com 108.162.192.95 AS13335, 172.64.32.95 AS13335, 173.245.58.95 AS13335, 2606:4700:50::adf5:3a5f AS13335, 2803:f800:50::6ca2:c05f AS13335, 2a06:98c1:50::ac40:205f AS13335
ram.ns.cloudflare.com 108.162.193.225 AS13335, 172.64.33.225 AS13335, 173.245.59.225 AS13335, 2606:4700:58::adf5:3be1 AS13335, 2803:f800:50::6ca2:c1e1 AS13335, 2a06:98c1:50::ac40:21e1 AS13335
agram.dkns1.dnshotel.dk 2a01:4f8:1c17:4999::2 AS24940, 88.99.120.238 AS24940
ns2.dnshotel.dk 2a01:4f8:c0c:4051::2 AS24940, 94.130.170.39 AS24940
agramkow.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
agramkowgroup.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
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