Domain report: aok.de

Registration

info

.de country-code

Found

TLD: .de (country-code)
ICANN policies apply: no

Checks

i

.de is a country-code TLD (ccTLD)

Country-code TLD: governed by its local registry under national policy, not by an ICANN contract. Registrar accreditation, dispute resolution and RDAP/WHOIS rules are set by the registry.

#1
✓ TLD delegated and signed #2

.de is delegated in the root zone and DNSSEC-signed.
i

Registration data not available

No registration data via RDAP: the registry of .de offers no RDAP service. Many ccTLD registries don't offer RDAP; check the registry's WHOIS instead.

#3

Delegation

warn

ns1.aok.de, ns2.aok.de, ns3.aok.de, ns4.aok.de

Found

Parent zone: de
Delegation from: a.nic.de (194.0.0.53)
NS at the parent: ns1.aok.de, ns2.aok.de, ns3.aok.de, ns4.aok.de
NS in the zone: ns1.aok.de, ns2.aok.de, ns3.aok.de, ns4.aok.de

Nameserver	Addresses	Network (AS)	Glue
ns1.aok.de	217.110.254.17	AS8220 COLT - COLT Technology Services Group Limited, GB	217.110.254.17
ns2.aok.de	217.110.254.18	AS8220 COLT - COLT Technology Services Group Limited, GB	217.110.254.18
ns3.aok.de	217.111.83.17	AS8220 COLT - COLT Technology Services Group Limited, GB	217.111.83.17
ns4.aok.de	217.111.83.18	AS8220 COLT - COLT Technology Services Group Limited, GB	217.111.83.18

Checks

✓ 4 nameservers #6

Delegated to ns1.aok.de, ns2.aok.de, ns3.aok.de, ns4.aok.de.
✓ Parent and zone agree #7

The parent delegation and the zone's NS records list the same nameservers.
✓ Glue present and correct #8

Glue is published for the nameservers inside the zone: ns1.aok.de, ns2.aok.de, ns3.aok.de, ns4.aok.de.
✓ All names resolve #9

Every nameserver name has an address and is not an alias.
✓ Nameservers in different networks #10

The nameservers are spread over 2 IPv4 /24s and 0 IPv6 /48s.
i

All nameservers in one AS

All nameserver addresses are announced by one network operator (AS8220 (COLT - COLT Technology Services Group Limited, GB): 4 addresses). An outage or attack on that network affects all nameservers; large anycast providers mitigate this, but a secondary DNS provider adds independence.

#11
i

All nameserver names under .de

All nameserver names are under one TLD, so a problem with that TLD also makes the nameservers unreachable. Some operators use names under two TLDs for extra resilience.

#12
!

No IPv6

None of the nameservers has an IPv6 address, so IPv6-only resolvers can't reach them.

#13

Nameservers

fail

2 of 4 addresses answer authoritatively

Found

Nameserver	Answer	Recursion	TCP / EDNS	AXFR	Version
ns1.aok.de 217.110.254.17	NOERROR, 4 ms, authoritative	no	yes / yes	refused	-
ns2.aok.de 217.110.254.18	NOERROR, 4 ms, authoritative	no	yes / yes	refused	-
ns3.aok.de 217.111.83.17	no response	no	no / no	-	-
ns4.aok.de 217.111.83.18	no response	no	no / no	-	-

Checks

✗

Nameservers not responding

These addresses did not answer, so resolvers waste time on timeouts: ns3.aok.de (217.111.83.17): read udp 46.225.38.91:57373->217.111.83.17:53: i/o timeout; ns4.aok.de (217.111.83.18): read udp 46.225.38.91:58731->217.111.83.18:53: i/o timeout.

#14
✓ All authoritative #15

Every responding nameserver answers authoritatively for the zone.
✓ No recursion #16

The nameservers do not answer recursive queries for other domains.
✓ No version disclosed #17

The nameservers don't reveal their software version.
✓ Zone transfers refused #18

No nameserver allows a zone transfer to the public.
✓ TCP supported #19

All nameservers answer over TCP.
✓ EDNS supported #20

All nameservers support EDNS(0).
✓ Public addresses #21

All nameserver addresses are publicly routable.

SOA

warn

serial 2026102152 · primary ns2.aok.de

Found

Primary (MNAME): ns2.aok.de
Contact (RNAME): domain-requests.colt.net
Serial: 2026102152
Refresh / retry: 3600 s / 1800 s
Expire: 604800 s
Negative TTL: 600 s

Serial per nameserver

Nameserver	Serial
ns1.aok.de (217.110.254.17)	2026102152
ns2.aok.de (217.110.254.18)	2026102137

Checks

!

Serials differ

The nameservers serve different versions of the zone: 2026102137 on ns2.aok.de (217.110.254.18); 2026102152 on ns1.aok.de (217.110.254.17). This is normal for a few minutes after a change; if it lasts, zone transfers to the secondaries are failing.

#22
✓ Timers within recommendations #23

SOA refresh 1h, retry 30m, expire 7d, negative TTL 10m.
✓ Primary is a public nameserver #24

The primary nameserver ns2.aok.de is one of the listed nameservers.
✓ Contact domain-requests@colt.net #25

The SOA RNAME domain-requests.colt.net means domain-requests@colt.net.
✓ Date-based serial #26

The serial 2026102152 follows the YYYYMMDDnn convention (2026-10-21).

DNSSEC

pass

Signed, DS published at parent

Found

Validated by resolver: yes
Denial of existence: NSEC3
NSEC3: 0 iterations, 0-byte salt
Signatures valid until: 30 October 2026

DS at the parent

Key tag	Algorithm	Digest	Matches a key
29326	ECDSAP256SHA256 (13)	SHA256 83BA450561F06139…	yes

DNSKEY in the zone

Key tag	Role	Algorithm
29326	KSK (257)	ECDSAP256SHA256 (13)
36919	ZSK (256)	ECDSAP256SHA256 (13)

Checks

✓ Signed and validated #27

The zone is signed, the parent publishes a DS record, and the resolver validates the answers.
✓ DS matches a key #28

The DS record at the parent matches a key in the zone: key tag 29326 (SHA256).
✓ Modern algorithms #29

Key algorithms: ECDSAP256SHA256 (13).
✓ Signatures valid until 2026-10-30 #30

The earliest DNSKEY/SOA signature expires at 2026-10-30 11:13 UTC.
✓ NSEC3 as recommended #31

The zone uses NSEC3 with 0 iterations and no salt (RFC 9276).

Records

info

13 records at the apex

Found

Read from: 217.110.254.17:53

Type	Value	TTL
SOA	ns2.aok.de. domain-requests.colt.net. 2026102152 3600 1800 604800 600	600
NS	ns2.aok.de.	600
NS	ns4.aok.de.	600
NS	ns3.aok.de.	600
NS	ns1.aok.de.	600
A	217.110.255.46	600
MX	10 mx1.aok.de.	600
MX	10 mx2.aok.de.	600
TXT	"google-site-verification=md9Sfv3gSEVsBjs3uN_emvnBU6qGe1X5zJiAUPhkdR0"	600
TXT	"v=spf1 include:_spf.aok.de -all"	600
TXT	"_71x9nn458nb1s3mkc3o9bnt3f2v1v1w"	600
TXT	"google-site-verification=ruFdOxK2XKBOzTxyrthJk9nz-o--X5DqP_faQWxe7sc"	600
TXT	"facebook-domain-verification=ki1dlz5hw91vc8k7jrpgj62pxmj08b"	600

Checks

✓ TTLs within range #32

TTLs: A 10m, MX 10m, NS 10m. The NS TTL at the parent is 1d and in the zone 10m; resolvers may use either.
✓ No CNAME at the apex #33

The zone apex has no CNAME record.
✓ No wildcard #34

Names that don't exist return NXDOMAIN.
i

No CAA records

Without CAA records any certificate authority may issue certificates for this domain. A CAA record limits issuance to the CAs you use.

#35