51.dk is a .dk domain served by 4 nameservers (ns1.simply.com, ns2.simply.com, ns3.simply.com and 1 more). It was registered on 12 February 2003 (WHOIS) and was already in the .dk zone when our tracking began on 16 June 2026. Its website address 93.191.156.101 is hosted by team.blue Denmark A/S (AS48854) in Denmark. Mail is handled by mx.simply.com. The zone is DNSSEC-signed and validates, has no DMARC policy and has no IPv6 address. Below are all of its DNS records from this scan: nameservers, A/AAAA, MX, TXT, SPF, DMARC, CAA, TLSA/DANE, MTA-STS, SRV and more.
| IP | TTL | PTR | ASN | ISP / Org | CIDR | Country | City |
|---|---|---|---|---|---|---|---|
| 93.191.156.101 | 3600s | linux222.unoeuro.com | AS48854 | team.blue Denmark A/S | 93.191.152.0/21 | 🇩🇰 Denmark | — |
| Priority | TTL | Mail Server | IP addresses | PTR | ASN |
|---|---|---|---|---|---|
| 10 | 3600s | mx.simply.com | 94.231.106.20 | mx.simply.com | AS48854 team.blue Denmark A/S |
| Service | CNAME / IP |
|---|---|
| 🔷 Autodiscover | 93.191.156.101 |
| 🔶 Autoconfig | maildiscover.simply.com → 94.231.108.222 |
| Service | Priority | Weight | Port | Target |
|---|---|---|---|---|
| _autodiscover._tcp | 10 | 10 | 443 | maildiscover.simply.com |
| TXT Record |
|---|
| v=spf1 include:spf.simply.com ?all |
| Policy | Record (51.dk) |
|---|---|
| ?all (neutral) | v=spf1 include:spf.simply.com ?all |
| www | 93.191.156.101 (AS48854) (address records, no CNAME) |
| www vs bare domain | Same network |
| 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 |
DNS lookups: 1/10 · policy: ?all
| Service / Owner | Type | Cert association |
|---|---|---|
| SMTP _25._tcp.mx.simply.com | DANE-EE · SPKI · SHA-256 | A9D603AF4D7ED6B9246B4B68500CD6F2… |
| SMTP _25._tcp.mx.simply.com | DANE-EE · SPKI · SHA-256 | 97A3BA009F39C761BFFB6574340E8138… |
| Check | Result |
|---|---|
| Validation Status | 🔒 Secure |
| AD Flag (resolver validates) | ✓ Set |
| DS Record | ✓ Found |
| DNSKEY Record | ✓ Found |
| Flags | fully validated |
| Field | Value |
|---|---|
| Serial | 2025042300 |
| Primary NS (MNAME) | ns1.simply.com |
| Responsible (RNAME) | hostmaster@simply.com |
| Refresh | 14400s |
| Retry | 3600s |
| Expire | 1209600s |
| Minimum (neg-cache TTL) | 3600s |
| Field | Value |
|---|---|
| Registrar | Simply.com A/S |
| Registered | 2003-02-12 |
| Expires | 2027-02-28 (134d) |
| Scanned At | Duration | Records | DNSSEC |
|---|---|---|---|
| 2026-10-01 12:10:14 | 376ms | 4 NS 1 A 1 MX | 🔒 Secure |
| 2026-09-13 13:55:16 | 513ms | 4 NS 1 A 1 MX | 🔒 Secure |
| 2026-08-27 07:00:30 | 712ms | 4 NS 1 A 1 MX | 🔒 Secure |
| 2026-07-04 11:40:59 shown | 4199ms | 4 NS 1 A 1 MX | 🔒 Secure |
| 2026-06-21 03:04:33 | 444ms | 4 NS 1 A 1 MX | ⚠️ Bogus |
| 2026-06-16 12:54:09 | 3167ms | 4 NS 1 A 1 MX | 🔒 Secure |