offthecoursebook.com - robtex.com
offthecoursebook.com
| DNSSEC | ⚠️ Not signed | ||||||
| A | 148.251.46.20🇩🇪 Hetzner148.251.0.0/16 HETZNER-RZ-BLK-ERX2 | ||||||
| PTR | static.20.46.251.148.clients.your-server.de | ||||||
| NS | hydrogen.ns.hetzner.com ⭐ | ||||||
| A | 2a01:4f8:0:1::add:1098🇩🇪 Hetzner2a01:4f8::/32 HETZNER-IPv6-BLK | ||||||
| PTR | hydrogen.ns.hetzner.com | ||||||
| A | 213.133.100.98🇩🇪 Hetzner213.133.96.0/19 HETZNER-RZ-NBG-BLK1 | ||||||
| PTR | hydrogen.ns.hetzner.com | ||||||
| NS | helium.ns.hetzner.de | ||||||
| A | 2001:67c:192c::add:5🇩🇪 NORIS-NETWORK2001:67c:192c::/48 | ||||||
| PTR | helium.ns.hetzner.de | ||||||
| A | 193.47.99.5🇩🇪 NORIS-NETWORK193.47.99.0/24 | ||||||
| PTR | helium.ns.hetzner.de | ||||||
| NS | oxygen.ns.hetzner.com | ||||||
| A | 2a01:4f8:0:1::add:2992🇩🇪 Hetzner2a01:4f8::/32 HETZNER-IPv6-BLK | ||||||
| PTR | oxygen.ns.hetzner.com | ||||||
| A | 88.198.229.192🇩🇪 Hetzner88.198.0.0/16 HETZNER-RZ-NBG-BLK4 | ||||||
| PTR | oxygen.ns.hetzner.com | ||||||
| MX | mail.offthecoursebook.com ⭐ | ||||||
| A | 148.251.46.20🇩🇪 Hetzner148.251.0.0/16 HETZNER-RZ-BLK-ERX2 | ||||||
| PTR | static.20.46.251.148.clients.your-server.de | ||||||
| TXT | v=spf1 ip4:144.76.90.20 -all | ||||||
| SOA | hydrogen.ns.hetzner.comdns@hetzner.com 2026-02-09 #0 | ||||||
com
| DNSSEC | 🔒 Signed (DS record present) | ||||||
| NS | a.gtld-servers.net ⭐ | ||||||
| NS | b.gtld-servers.net | ||||||
| NS | c.gtld-servers.net | ||||||
| NS | d.gtld-servers.net | ||||||
| NS | e.gtld-servers.net | ||||||
| NS | f.gtld-servers.net | ||||||
| NS | g.gtld-servers.net | ||||||
| NS | h.gtld-servers.net | ||||||
| NS | i.gtld-servers.net | ||||||
| NS | j.gtld-servers.net | ||||||
| NS | k.gtld-servers.net | ||||||
| NS | l.gtld-servers.net | ||||||
| NS | m.gtld-servers.net | ||||||
| SOA | a.gtld-servers.netnstld@verisign-grs.com serial=1774695152 | ||||||
Subdomains
mail.offthecoursebook.com |
Same first word
offthecoursebook.com |
DNS History
6 records (5 active, 1 former)
●NShelium.ns.hetzner.de2026-02-15 → 2026-03-28 · 2 obs
● 2026-03-28 10:53:40
●NShydrogen.ns.hetzner.com2026-02-15 → 2026-03-28 · 2 obs
● 2026-03-28 10:53:40
●NSoxygen.ns.hetzner.com2026-02-15 → 2026-03-28 · 2 obs
● 2026-03-28 10:53:40
●MXmail.offthecoursebook.com2026-02-15 → 2026-03-28 · 2 obs
● 2026-03-28 10:53:40
○A144.76.90.202026-02-15 → 2026-03-28 · 2 obs
○ 2026-03-28 10:53:40
●A148.251.46.202026-02-15 → 2026-03-28 · 2 obs
● 2026-03-28 10:53:40
🔍 DNS Trace
📋 Delegation Chain
| Zone | Nameservers | Glue |
|---|---|---|
| com | a.gtld-servers.net, b.gtld-servers.net, c.gtld-servers.net, d.gtld-servers.net... | - |
| offthecoursebook.com | helium.ns.hetzner.de, hydrogen.ns.hetzner.com, oxygen.ns.hetzner.com | 2 records |
✅ Authoritative Response
Server:193.47.99.5
NS records: helium.ns.hetzner.de, hydrogen.ns.hetzner.com, oxygen.ns.hetzner.com
🔒 DNSSEC Status
⚠️ Insecure (no DNSSEC)
No DS record for offthecoursebook.com (unsigned zone)
⏱️ Timing
Total: 727ms | Queries: -
📄 Records
| Type | Count | Sample Data |
|---|---|---|
| A | 1 | 148.251.46.20 |
| NS | 3 | hydrogen.ns.hetzner.com, oxygen.ns.hetzner.com... |
| MX | 1 | mail.offthecoursebook.com (pri: 10) |
| TXT | 1 | v=spf1 ip4:144.76.90.20 -all |
| SOA | 1 | hydrogen.ns.hetzner.com dns.hetzner.com |
📌 Glue Records Collected
Total: 2
Out-of-bailiwick: 2 (hydrogen.ns.hetzner.com, oxygen.ns.hetzner.com)
Analysis
Hierarchy
offthecoursebook.com is parent of mail.offthecoursebook.com.
IP Addresses
offthecoursebook.com points to a single IP: 148.251.46.20.
Other host names, for instance a-i.at, mail.offthecoursebook.com and ecklmair.at share IP numbers with offthecoursebook.com.
Name Servers
offthecoursebook.com is delegated to three name servers: hydrogen.ns.hetzner.com, oxygen.ns.hetzner.com and helium.ns.hetzner.de.
offthecoursebook.com at least partially shares its name servers with other domains, for instance novitec.net, callcentercom.de, bama.in, tagea.app and cbs-ea.com.
These name servers are commonly used with ns1.first-ns.de, robotns2.second-ns.de and robotns3.second-ns.com.
Host names with two IP numbers:
hydrogen.ns.hetzner.com points to: 2a01:4f8:0:1::add:1098 and 213.133.100.98.
oxygen.ns.hetzner.com points to: 2a01:4f8:0:1::add:2992 and 88.198.229.192.
helium.ns.hetzner.de points to: 2001:67c:192c::add:5 and 193.47.99.5.
Mail Servers
offthecoursebook.com is served by a single mail server, mail.offthecoursebook.com.
mail.offthecoursebook.com points to IP number 148.251.46.20.