u21.dk

Records from scan: 2026-10-03 02:35:07 · 780ms total · last checked 2026-10-16 16:38 (unchanged)

⬇ Zone File 📜 Timeline & History ⚡ Scan Now

u21.dk is a .dk domain served by 3 nameservers (ns1.simply.com, ns2.simply.com, ns3.simply.com). It was registered on 21 January 2025 (WHOIS) and was already in the .dk zone when our tracking began on 16 June 2026. Its website address 188.228.54.119 is hosted by Altibox Danmark AS (AS214875) in Denmark. Mail is handled by mail.7a.dk. The zone is DNSSEC-signed and validates, publishes a DMARC policy and has no IPv6 address. Below are all of its DNS records from our latest scan: nameservers, A/AAAA, MX, TXT, SPF, DMARC, CAA, TLSA/DANE, MTA-STS, SRV and more.

🖥️ Nameservers#

3 records 48ms

Nameserver	IP addresses	PTR	ASN / ISP
ns1.simply.com	2a02:2339:1:15c::4562:4562 91.197.248.78	ns1.simply.com ns1.simply.com	AS48854 team.blue Denmark A/S AS48854 team.blue Denmark A/S
ns2.simply.com	185.25.141.15 2a02:2339:4006:101::4562:4562	ns2.simply.com ns2.simply.com	AS48854 team.blue Denmark A/S AS48854 team.blue Denmark A/S
ns3.simply.com	91.197.248.79	ns3.simply.com	AS48854 team.blue Denmark A/S

🌍 A Records#

1 records 44ms

IP	TTL	PTR	ASN	ISP / Org	CIDR	Country	City
188.228.54.119	3600s	188.228.54.119.dynamic.altibox.net	AS214875	Altibox Danmark AS	188.228.54.0/24	🇩🇰 Denmark	Sæby

📧 MX Records#

1 records 60ms

Priority	TTL	Mail Server	IP addresses	PTR	ASN
0	3600s	mail.7a.dk	188.228.54.119	188.228.54.119.dynamic.altibox.net	AS214875 Altibox Danmark AS

📧 Autodiscover / Autoconfig#

Service	CNAME / IP
🔷 Autodiscover	188.228.54.119
🔶 Autoconfig	188.228.54.119

🔷 AAAA Records (IPv6)#

✗ No AAAA records — IPv6 not configured

🔐 HTTPS Records#

✗ No HTTPS RR — no SVCB/HTTPS service binding

📝 TXT Records#

1 records 137ms

TXT Record
v=spf1 include:spf.mailjet.com include:spf.simply.com -all

✉️ SPF#

Policy	Record (u21.dk)
-all (hard fail)	v=spf1 include:spf.mailjet.com include:spf.simply.com -all

📨 DMARC#

Policy	Record (_dmarc.u21.dk)
p=none (monitor only)	v=DMARC1; p=none;

📬 MTA-STS#

✗ No MTA-STS policy — SMTP TLS not enforced

📈 TLSRPT#

✗ No TLSRPT record — no SMTP TLS failure reporting

📜 CAA Records#

✗ No CAA records — any CA may issue certificates

🧩 Web & zone#

checked 2026-10-11 09:07:10

www	188.228.54.119 (AS214875) (address records, no CNAME)
www vs bare domain	Same network u21.dk: 188.228.54.119 (AS214875) www.u21.dk: 188.228.54.119 (AS214875)
Wildcard	Yes: any name under the zone resolves
Denial of existence	NSEC zone can be walked (all names enumerable)
CDS / CDNSKEY	Published: key rollovers can be automated with the registry (RFC 7344/8078) 1 CDS, 1 CDNSKEY

🔎 SPF check#

zone-wide SPF report

DNS lookups: 2/10 · policy: -all

No problems found

🔗 TLSA / DANE#

✗ No TLSA records — DANE not configured for HTTPS (_443) or MX (_25)

🔐 DNSSEC#

128ms

Check	Result
Validation Status	🔒 Secure
AD Flag (resolver validates)	✓ Set
DS Record	✓ Found
DNSKEY Record	✓ Found
Flags	fully validated

🏷️ SOA#

33ms

Field	Value
Serial	2026100200
Primary NS (MNAME)	ns1.simply.com
Responsible (RNAME)	hostmaster@simply.com
Refresh	14400s
Retry	3600s
Expire	1209600s
Minimum (neg-cache TTL)	3600s

📋 Registration#

WHOIS fetched 2026-10-11 23:03:33

Field	Value
Registrar	Punktum dk A/S (direct)
Registered	2025-01-21
Expires	2027-01-20 (95d)

📋 WHOIS#

⏱️ Lookup Timing#

48ms

44ms

60ms

AAAA

52ms

TXT

137ms

CAA

54ms

HTTPS

46ms

TLSA

142ms

SOA

33ms

MTA-STS

75ms

DNSSEC

128ms

SRV

64ms

Total

780ms

🕐 Scan History#

Scanned At	Duration	Records	DNSSEC
2026-10-03 02:35:07 shown	780ms	3 NS 1 A 1 MX	🔒 Secure
2026-09-09 09:28:06	602ms	3 NS 1 A 1 MX	🔒 Secure
2026-08-31 12:06:09	661ms	3 NS 1 A 1 MX	🔒 Secure
2026-08-30 06:59:47	1116ms	3 NS 0 A 1 MX	🔒 Secure
2026-08-29 00:01:53	643ms	3 NS 1 A 1 MX	🔒 Secure
2026-08-27 23:52:20	808ms	3 NS 1 A 1 MX	🔒 Secure
2026-08-27 02:11:21	566ms	3 NS 1 A 1 MX	🔒 Secure
2026-08-08 07:11:21	741ms	3 NS 1 A 1 MX	🔒 Secure
2026-07-03 09:00:41	2473ms	3 NS 1 A 1 MX	🔒 Secure
2026-06-27 21:11:59	1177ms	3 NS 1 A 1 MX	🔒 Secure
2026-06-26 01:23:11	434ms	3 NS 1 A 1 MX	🔒 Secure
2026-06-22 10:15:52	1166ms	0 NS 0 A 0 MX	❓ Unknown
2026-06-18 04:07:30	662ms	3 NS 1 A 1 MX	🔒 Secure