undertow.dk is a .dk domain served by 2 nameservers (ns01.one.com, ns02.one.com). It was registered on 3 December 1999 (WHOIS) and was already in the .dk zone when our tracking began on 16 June 2026. Its website address 87.104.83.156 is hosted by AURA Fiber A/S (AS204274) in Denmark. Mail is handled by mx.upnavigator.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.
| IP | TTL | PTR | ASN | ISP / Org | CIDR | Country | City |
|---|---|---|---|---|---|---|---|
| 87.104.83.156 | 3600s | mx.upnavigator.dk | AS204274 | AURA Fiber A/S | 87.104.64.0/18 | 🇩🇰 Denmark | Odder |
| Priority | TTL | Mail Server | IP addresses | PTR | ASN |
|---|---|---|---|---|---|
| 10 | 3600s | mx.upnavigator.dk | 87.104.83.156 | mx.upnavigator.dk | AS204274 AURA Fiber A/S |
| Service | CNAME / IP |
|---|---|
| 🔷 Autodiscover | undertow.dk → 87.104.83.156 |
| 🔶 Autoconfig | undertow.dk → 87.104.83.156 |
| TXT Record |
|---|
| v=spf1 a mx a:mx.upnavigator.dk ip4:87.104.83.156 ~all |
| Policy | Record (undertow.dk) |
|---|---|
| ~all (soft fail) | v=spf1 a mx a:mx.upnavigator.dk ip4:87.104.83.156 ~all |
| Policy | Record (_dmarc.undertow.dk) |
|---|---|
| p=quarantine | v=DMARC1;p=quarantine;sp=quarantine;pct=100;rua=mailto:info@upnavigator.dk;ruf=mailto:info@upnavigator.dk;rf=afrf;ri=86400;fo=1 |
| Flags | Tag | Value |
|---|---|---|
| 0 | issue | letsencrypt.org |
| www | 87.104.83.156 (AS204274) (address records, no CNAME) |
| www vs bare domain | Same network |
| Wildcard | Yes: any name under the zone resolves |
| CDS / CDNSKEY | None 0 CDS, 0 CDNSKEY |
| Selector | CNAME | Key |
|---|---|---|
| dkim | — | RSA · ~1024 bit below 2048 bit |
DKIM selectors can't be listed, so we check the common ones (Microsoft 365, Google, Mailchimp, SendGrid, generic). Keys under other selectors aren't shown.
DNS lookups: 3/10 · policy: ~all
No problems found| Type | Name | Value |
|---|---|---|
| CNAME | _acme-challenge.undertow.dk | undertow.dk |
| Check | Result |
|---|---|
| Validation Status | 🔒 Secure |
| AD Flag (resolver validates) | ✓ Set |
| DS Record | ✓ Found |
| DNSKEY Record | ✓ Found |
| Flags | fully validated |
| Field | Value |
|---|---|
| Serial | 2026092001 |
| Primary NS (MNAME) | ns01.one.com |
| Responsible (RNAME) | hostmaster@one.com |
| Refresh | 14400s |
| Retry | 3600s |
| Expire | 1209600s |
| Minimum (neg-cache TTL) | 600s |
| Field | Value |
|---|---|
| Registrar | Punktum dk A/S (direct) |
| Registered | 1999-12-03 |
| Expires | 2026-12-31 (75d) |
| Scanned At | Duration | Records | DNSSEC |
|---|---|---|---|
| 2026-09-23 15:58:49 shown | 677ms | 2 NS 1 A 1 MX | 🔒 Secure |
| 2026-07-28 00:54:33 | 6730ms | 2 NS 1 A 1 MX | 🔒 Secure |
| 2026-06-25 07:31:26 | 665ms | 2 NS 1 A 1 MX | 🔒 Secure |
| 2026-06-17 23:50:09 | 1282ms | 2 NS 1 A 1 MX | 🔒 Secure |