🛡️ 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
zwater.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
zwaves.dkns1.designrus.dk 176.9.4.22 AS24940, 2a01:4f8:141:3416::2 AS24940
ns2.designrus.dk 2a01:4f8:242:5649::2 AS24940, 49.12.124.182 AS24940
zwcad.dkns-1444.awsdns-52.org 205.251.197.164 AS16509, 2600:9000:5305:a400::1 AS16509
ns-2007.awsdns-58.co.uk 205.251.199.215 AS16509, 2600:9000:5307:d700::1 AS16509
ns-460.awsdns-57.com 205.251.193.204 AS16509, 2600:9000:5301:cc00::1 AS16509
ns-656.awsdns-18.net 205.251.194.144 AS16509, 2600:9000:5302:9000::1 AS16509
zweck.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
zweeler.dkns-1123.awsdns-12.org 205.251.196.99 AS16509, 2600:9000:5304:6300::1 AS16509
ns-1915.awsdns-47.co.uk 205.251.199.123 AS16509, 2600:9000:5307:7b00::1 AS16509
ns-311.awsdns-38.com 205.251.193.55 AS16509, 2600:9000:5301:3700::1 AS16509
ns-526.awsdns-01.net 205.251.194.14 AS16509, 2600:9000:5302:e00::1 AS16509
zweep.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
zweeper.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
zwei.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
zweidorff.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
zweigrosse.dkabby.ns.cloudflare.com 108.162.192.100 AS13335, 172.64.32.100 AS13335, 173.245.58.100 AS13335, 2606:4700:50::adf5:3a64 AS13335, 2803:f800:50::6ca2:c064 AS13335, 2a06:98c1:50::ac40:2064 AS13335
marek.ns.cloudflare.com 108.162.193.202 AS13335, 172.64.33.202 AS13335, 173.245.59.202 AS13335, 2606:4700:58::adf5:3bca AS13335, 2803:f800:50::6ca2:c1ca AS13335, 2a06:98c1:50::ac40:21ca AS13335
zwergiushoff.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
zwgroup.dkhorizon.dns-parking.com 172.64.53.161 AS13335, 2606:4700:5a::ac40:35a1 AS13335
orbit.dns-parking.com 172.64.52.95 AS13335, 2606:4700:52::ac40:345f AS13335
zwicki.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
zwillinge.dkns1.web24tech.com 85.215.129.49 AS8560
ns2.web24tech.com 85.215.133.5 AS8560
zwip.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
zwischenraum.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
zwixton.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
zwonko.dkns1.dlx.dk 2a00:1b18:1337:1337::53 AS47527, 46.30.121.210 AS47527
ns2.dlx.dk 185.208.212.124 AS47527, 2a00:1b19:1337:1337::53 AS47527
zwoop.dkholly.ns.cloudflare.com 108.162.194.133 AS13335, 162.159.38.133 AS13335, 172.64.34.133 AS13335, 2606:4700:50::a29f:2685 AS13335, 2803:f800:50::6ca2:c285 AS13335, 2a06:98c1:50::ac40:2285 AS13335
jack.ns.cloudflare.com 108.162.193.121 AS13335, 172.64.33.121 AS13335, 173.245.59.121 AS13335, 2606:4700:58::adf5:3b79 AS13335, 2803:f800:50::6ca2:c179 AS13335, 2a06:98c1:50::ac40:2179 AS13335
zwoosh.dkholly.ns.cloudflare.com 108.162.194.133 AS13335, 162.159.38.133 AS13335, 172.64.34.133 AS13335, 2606:4700:50::a29f:2685 AS13335, 2803:f800:50::6ca2:c285 AS13335, 2a06:98c1:50::ac40:2285 AS13335
jack.ns.cloudflare.com 108.162.193.121 AS13335, 172.64.33.121 AS13335, 173.245.59.121 AS13335, 2606:4700:58::adf5:3b79 AS13335, 2803:f800:50::6ca2:c179 AS13335, 2a06:98c1:50::ac40:2179 AS13335
zwp.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
zww.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
zwz.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
zx-r.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
zx14q.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
zx81.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
zxcvbn.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
zxello.dkisaac.ns.cloudflare.com 108.162.193.177 AS13335, 172.64.33.177 AS13335, 173.245.59.177 AS13335, 2606:4700:58::adf5:3bb1 AS13335, 2803:f800:50::6ca2:c1b1 AS13335, 2a06:98c1:50::ac40:21b1 AS13335
sue.ns.cloudflare.com 108.162.192.145 AS13335, 172.64.32.145 AS13335, 173.245.58.145 AS13335, 2606:4700:50::adf5:3a91 AS13335, 2803:f800:50::6ca2:c091 AS13335, 2a06:98c1:50::ac40:2091 AS13335
zxellonet.dkisaac.ns.cloudflare.com 108.162.193.177 AS13335, 172.64.33.177 AS13335, 173.245.59.177 AS13335, 2606:4700:58::adf5:3bb1 AS13335, 2803:f800:50::6ca2:c1b1 AS13335, 2a06:98c1:50::ac40:21b1 AS13335
sue.ns.cloudflare.com 108.162.192.145 AS13335, 172.64.32.145 AS13335, 173.245.58.145 AS13335, 2606:4700:50::adf5:3a91 AS13335, 2803:f800:50::6ca2:c091 AS13335, 2a06:98c1:50::ac40:2091 AS13335
zxf.dkns1-05.azure-dns.com 13.107.236.5 AS8075, 2603:1061:0:700::5 AS8075
ns2-05.azure-dns.net 150.171.21.5 AS8075, 2620:1ec:8ec:700::5 AS8075
ns3-05.azure-dns.org 204.14.183.5 AS8075, 2a01:111:4000:700::5 AS8075
ns4-05.azure-dns.info 208.84.5.5 AS8075, 2620:1ec:bda:700::5 AS8075
zxl.dkns13.hawkhost.com 198.252.96.160 AS20473
ns14.hawkhost.com 198.252.97.160 AS20473
zxmail.dkbart.ns.cloudflare.com 108.162.193.71 AS13335, 172.64.33.71 AS13335, 173.245.59.71 AS13335, 2606:4700:58::adf5:3b47 AS13335, 2803:f800:50::6ca2:c147 AS13335, 2a06:98c1:50::ac40:2147 AS13335
phoenix.ns.cloudflare.com 108.162.194.201 AS13335, 162.159.38.201 AS13335, 172.64.34.201 AS13335, 2606:4700:50::a29f:26c9 AS13335, 2803:f800:50::6ca2:c2c9 AS13335, 2a06:98c1:50::ac40:22c9 AS13335
zxr.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
zxspectrum.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
zxt.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
zxv.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
zxx.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
zxxz.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
zxy.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
zxzx.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
zy.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
zyagent.dkns1-09.azure-dns.com 13.107.236.9 AS8075, 2603:1061:0:700::9 AS8075
ns2-09.azure-dns.net 150.171.21.9 AS8075, 2620:1ec:8ec:700::9 AS8075
ns3-09.azure-dns.org 204.14.183.9 AS8075, 2a01:111:4000:700::9 AS8075
ns4-09.azure-dns.info 208.84.5.9 AS8075, 2620:1ec:bda:700::9 AS8075
zyber.dkns1.dlx.dk 2a00:1b18:1337:1337::53 AS47527, 46.30.121.210 AS47527
ns2.dlx.dk 185.208.212.124 AS47527, 2a00:1b19:1337:1337::53 AS47527
zyberbrains.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
zybercity.dkns1.vths.dk 116.203.116.214 AS24940
ns2.vths.dk 195.201.236.251 AS24940
ns3.vths.dk 95.216.207.224 AS24940
zyberdata.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
zybermail.dksage.ns.cloudflare.com 108.162.195.236 AS13335, 162.159.44.236 AS13335, 172.64.35.236 AS13335, 2606:4700:58::a29f:2cec AS13335, 2803:f800:50::6ca2:c3ec AS13335, 2a06:98c1:50::ac40:23ec AS13335
veronica.ns.cloudflare.com 108.162.194.173 AS13335, 162.159.38.173 AS13335, 172.64.34.173 AS13335, 2606:4700:50::a29f:26ad AS13335, 2803:f800:50::6ca2:c2ad AS13335, 2a06:98c1:50::ac40:22ad AS13335
zybernaut.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
zybernauts.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
zyberspace.dkns1.vths.dk 116.203.116.214 AS24940
ns2.vths.dk 195.201.236.251 AS24940
ns3.vths.dk 95.216.207.224 AS24940
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