🛡️ 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

1,186,235 working delegations with resolvable nameservers (lame excluded)
Every nameserver is on…DomainsShareWhy it matters
A single nameserver host1510.01%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 IPv610,8040.91%All nameservers share one network: a routing problem there takes them all down.
One autonomous system756,41863.8%Common and usually fine with a large provider, but one network outage still takes all nameservers down.
No IPv6 nameserver85,9667.2%IPv6-only resolvers cannot reach the zone.

Click a row to list its domains (computed 2026-09-30 13:10).

📋 One autonomous system

756,418 domains
DomainNameservers and addresses
zayami.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
zayan.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
zayn.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
zaytoon.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
zaz.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
zazamusic.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
zazaspita.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
zazen.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
zazencopenhagen.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
zazoo.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
marty.ns.cloudflare.com 108.162.193.204 AS13335, 172.64.33.204 AS13335, 173.245.59.204 AS13335, 2606:4700:58::adf5:3bcc AS13335, 2803:f800:50::6ca2:c1cc AS13335, 2a06:98c1:50::ac40:21cc AS13335
zazu.dkkaiser.ns.cloudflare.com 108.162.195.9 AS13335, 162.159.44.9 AS13335, 172.64.35.9 AS13335, 2606:4700:58::a29f:2c09 AS13335, 2803:f800:50::6ca2:c309 AS13335, 2a06:98c1:50::ac40:2309 AS13335
simone.ns.cloudflare.com 108.162.194.26 AS13335, 162.159.38.26 AS13335, 172.64.34.26 AS13335, 2606:4700:50::a29f:261a AS13335, 2803:f800:50::6ca2:c21a AS13335, 2a06:98c1:50::ac40:221a AS13335
zazuweb.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
zb.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
zbbc.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
zbc-gourmetbutikken.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
zbc-skærehallernes-konferencecenter.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
zbclabs.dkmatteo.ns.cloudflare.com 108.162.195.224 AS13335, 162.159.44.224 AS13335, 172.64.35.224 AS13335, 2606:4700:58::a29f:2ce0 AS13335, 2803:f800:50::6ca2:c3e0 AS13335, 2a06:98c1:50::ac40:23e0 AS13335
nataly.ns.cloudflare.com 108.162.194.101 AS13335, 162.159.38.101 AS13335, 172.64.34.101 AS13335, 2606:4700:50::a29f:2665 AS13335, 2803:f800:50::6ca2:c265 AS13335, 2a06:98c1:50::ac40:2265 AS13335
zbclearn.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
zbconline.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
zbiotics.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
zbj.dkkenia.ns.cloudflare.com 108.162.194.93 AS13335, 162.159.38.93 AS13335, 172.64.34.93 AS13335, 2606:4700:50::a29f:265d AS13335, 2803:f800:50::6ca2:c25d AS13335, 2a06:98c1:50::ac40:225d AS13335
maxim.ns.cloudflare.com 108.162.195.198 AS13335, 162.159.44.198 AS13335, 172.64.35.198 AS13335, 2606:4700:58::a29f:2cc6 AS13335, 2803:f800:50::6ca2:c3c6 AS13335, 2a06:98c1:50::ac40:23c6 AS13335
zbk.dkaida.ns.cloudflare.com 108.162.192.58 AS13335, 172.64.32.58 AS13335, 173.245.58.58 AS13335, 2606:4700:50::adf5:3a3a AS13335, 2803:f800:50::6ca2:c03a AS13335, 2a06:98c1:50::ac40:203a AS13335
margo.ns.cloudflare.com 108.162.195.144 AS13335, 162.159.44.144 AS13335, 172.64.35.144 AS13335, 2606:4700:58::a29f:2c90 AS13335, 2803:f800:50::6ca2:c390 AS13335, 2a06:98c1:50::ac40:2390 AS13335
zbm.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
zbot.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
zbr.dklou.ns.cloudflare.com 108.162.193.199 AS13335, 172.64.33.199 AS13335, 173.245.59.199 AS13335, 2606:4700:58::adf5:3bc7 AS13335, 2803:f800:50::6ca2:c1c7 AS13335, 2a06:98c1:50::ac40:21c7 AS13335
ryleigh.ns.cloudflare.com 108.162.194.198 AS13335, 162.159.38.198 AS13335, 172.64.34.198 AS13335, 2606:4700:50::a29f:26c6 AS13335, 2803:f800:50::6ca2:c2c6 AS13335, 2a06:98c1:50::ac40:22c6 AS13335
zbrah.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
zbs.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
zbtoemrer.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
zbtømrer.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
zbz.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
zcamp.dkns1.ispapi.net 194.50.187.134 AS1921, 2a04:2b00:14cc::4 AS1921
ns2.ispapi.net 194.0.182.1 AS1921, 2a04:2b00:14dd::4 AS1921
zcash.dkcortney.ns.cloudflare.com 108.162.192.87 AS13335, 172.64.32.87 AS13335, 173.245.58.87 AS13335, 2606:4700:50::adf5:3a57 AS13335, 2803:f800:50::6ca2:c057 AS13335, 2a06:98c1:50::ac40:2057 AS13335
ernest.ns.cloudflare.com 108.162.193.164 AS13335, 172.64.33.164 AS13335, 173.245.59.164 AS13335, 2606:4700:58::adf5:3ba4 AS13335, 2803:f800:50::6ca2:c1a4 AS13335, 2a06:98c1:50::ac40:21a4 AS13335
zcd.dkanahi.ns.cloudflare.com 108.162.194.24 AS13335, 162.159.38.24 AS13335, 172.64.34.24 AS13335, 2606:4700:50::a29f:2618 AS13335, 2803:f800:50::6ca2:c218 AS13335, 2a06:98c1:50::ac40:2218 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
zcdskole.dkns8.wixdns.net 216.239.32.101 AS15169
ns9.wixdns.net 216.239.34.101 AS15169
zcharrlodt.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
zcld.dkcloe.ns.cloudflare.com 108.162.192.86 AS13335, 172.64.32.86 AS13335, 173.245.58.86 AS13335, 2606:4700:50::adf5:3a56 AS13335, 2803:f800:50::6ca2:c056 AS13335, 2a06:98c1:50::ac40:2056 AS13335
hans.ns.cloudflare.com 108.162.193.175 AS13335, 172.64.33.175 AS13335, 173.245.59.175 AS13335, 2606:4700:58::adf5:3baf AS13335, 2803:f800:50::6ca2:c1af AS13335, 2a06:98c1:50::ac40:21af AS13335
zcommodities.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
zcore.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
zct.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
zcuba.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
zcx.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
zczc.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
zday.dkns1.fab-it.dk 2a00:df0:114:253:: AS45032, 93.90.114.253 AS45032
ns2.fab-it.dk 2a00:df0:114:63:: AS45032, 93.90.114.63 AS45032
ns3.fab-it.dk 2a00:df0:115:253:: AS45032, 93.90.115.253 AS45032
zdc.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
zdd.dked.ns.cloudflare.com 108.162.193.111 AS13335, 172.64.33.111 AS13335, 173.245.59.111 AS13335, 2606:4700:58::adf5:3b6f AS13335, 2803:f800:50::6ca2:c16f AS13335, 2a06:98c1:50::ac40:216f AS13335
jillian.ns.cloudflare.com 108.162.194.44 AS13335, 162.159.38.44 AS13335, 172.64.34.44 AS13335, 2606:4700:50::a29f:262c AS13335, 2803:f800:50::6ca2:c22c AS13335, 2a06:98c1:50::ac40:222c AS13335
zde.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
zdralic.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
zds.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
zdyb.dkdns1.p04.nsone.net 198.51.44.4 AS62597, 2620:4d:4000:6259:7:4:0:1 AS62597
dns2.p04.nsone.net 198.51.45.4 AS62597, 2a00:edc0:6259:7:4::2 AS62597
dns3.p04.nsone.net 198.51.44.68 AS62597, 2620:4d:4000:6259:7:4:0:3 AS62597
dns4.p04.nsone.net 198.51.45.68 AS62597, 2a00:edc0:6259:7:4::4 AS62597
zdæk.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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