u21.dk DNS records

🖥️ Nameservers3 records 22ms

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 Records1 records 26ms

IP	TTL	PTR	ASN	ISP / Org	CIDR	Country	City
188.228.54.137	3600s	188.228.54.137.dynamic.altibox.net	AS214875	Altibox Danmark AS	188.228.54.0/24	🇩🇰 Denmark	Give

📧 MX Records1 records 24ms

Priority	TTL	Mail Server	IP addresses	PTR	ASN
0	3600s	mail.7a.dk	188.228.54.137 2a00:fd01:8146:3d00::30	188.228.54.137.dynamic.altibox.net —	AS214875 Altibox Danmark AS AS214875 Altibox Danmark AS

📧 Autodiscover / Autoconfig

Service	CNAME / IP
🔷 Autodiscover	188.228.54.137
🔶 Autoconfig	188.228.54.137

🔷 AAAA Records (IPv6)1 records 27ms

IPv6 Address	TTL	PTR	ASN	ISP / Org	CIDR	Country	City
2a00:fd01:8146:3d00:215:5dff:fe02:6d04	600s	—	AS214875	Altibox Danmark AS	2a00:fd01:0:0:0:0:0:0/32	🇩🇰 Denmark	Holstebro

🔐 HTTPS Records

✗ No HTTPS RR — no SVCB/HTTPS service binding

📝 TXT Records1 records 78ms

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

🔗 TLSA / DANE

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

🔐 DNSSEC95ms

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

🏷️ SOA0ms

Field	Value
Serial	2026083101
Primary NS (MNAME)	ns1.simply.com
Responsible (RNAME)	hostmaster@simply.com
Refresh	14400s
Retry	3600s
Expire	1209600s
Minimum (neg-cache TTL)	3600s

📋 Registration

✗ No registration data — collected automatically when SOA serial changes

📋 WHOIS

⏱️ Lookup Timing

NS

22ms

A

26ms

MX

24ms

AAAA

27ms

TXT

78ms

CAA

19ms

HTTPS

21ms

TLSA

236ms

SOA

0ms

MTA-STS

35ms

DNSSEC

95ms

SRV

29ms

Total

661ms

🕐 Scan History

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