zero.cz - dns.ninja
zero.cz
| DNSSEC | ⚠️ Not signed | ||||||
| A | 81.91.91.54🇨🇿 WEB4U81.91.88.0/21 | ||||||
| PTR | wm108.web-media.cz | ||||||
| NS | ns2.web4u.cz ⭐ | ||||||
| A | 2a02:a40:100:28ff::12🇨🇿 BlueTone-AS2a02:a40::/32 Ceske Radiokomunikace, a.s. | ||||||
| PTR | ns2.web4u.cz | ||||||
| A | 85.207.53.12🇨🇿 BlueTone-AS85.207.0.0/16 BlueTone-CRa-CZ Fourth address block | ||||||
| PTR | ns2.web4u.cz | ||||||
| NS | ns.web4u.cz | ||||||
| A | 2001:1568:fd::241🇨🇿 WEB4U2001:1568::/33 | ||||||
| PTR | ns.web4u.cz | ||||||
| A | 185.14.224.241🇨🇿 WEB4U185.14.224.0/23 | ||||||
| PTR | ns.web4u.cz | ||||||
| MX | mail.zero.cz ⭐ | ||||||
| A | 81.91.84.134🇨🇿 WEB4U81.91.80.0/21 | ||||||
| PTR | m105.server4u.cz | ||||||
| TXT | v=spf1 a mx ptr ip4:81.91.85.148 include:_emailing.heureka.cz ~all | ||||||
| SOA | ns.web4u.czadmin@web4u.cz 2008-09-30 #1 | ||||||
cz
| DNSSEC | 🔒 Signed (DS record present) | ||||||
| NS | a.ns.nic.cz ⭐ | ||||||
| NS | b.ns.nic.cz | ||||||
| NS | c.ns.nic.cz | ||||||
| NS | d.ns.nic.cz | ||||||
| SOA | a.ns.nic.czhostmaster@nic.cz serial=1786967261 | ||||||
Subdomains
mail.zero.cz |
Same first word
Similar names
DNS History
5 records (4 active, 1 former)
●MXmail.zero.cz2015-07-26 → 2026-08-17 · 2 obs
● 2026-08-17 12:19:34
○A81.91.84.1762015-07-26 → 2021-06-17 · 4 obs
● 2021-06-17 20:54:32
○ 2026-03-13 04:17:48
○ 2026-08-17 12:19:34
●A81.91.91.542026-03-13 → 2026-08-17 · 3 obs
● 2026-03-13 04:17:48
● 2026-08-17 12:19:34
🔍 DNS Trace
📋 Delegation Chain
| Zone | Nameservers | Glue |
|---|---|---|
| cz | a.ns.nic.cz, b.ns.nic.cz, c.ns.nic.cz, d.ns.nic.cz | - |
| zero.cz | ns.web4u.cz, ns2.web4u.cz | 4 records |
✅ Authoritative Response
Server:185.14.224.241
NS records: ns.web4u.cz, ns2.web4u.cz
🔒 DNSSEC Status
⚠️ Insecure (no DNSSEC)
No DS record for zero.cz (unsigned zone)
⏱️ Timing
Total: 939ms | Queries: -
📄 Records
| Type | Count | Sample Data |
|---|---|---|
| A | 1 | 81.91.91.54 |
| NS | 2 | ns.web4u.cz, ns2.web4u.cz |
| MX | 1 | mail.zero.cz (pri: 10) |
| TXT | 1 | v=spf1 a mx ptr ip4:81.91.85.148 include |
| SOA | 1 | ns.web4u.cz admin.web4u.cz |
📌 Glue Records Collected
Total: 4
Out-of-bailiwick: 4 (ns.web4u.cz, ns.web4u.cz, ns2.web4u.cz...)
Analysis
Hierarchy
zero.cz is the parent zone for mail.zero.cz.
IP Addresses
zero.cz resolves to just one IP address, 81.91.91.54.
Two other host names, along with lamda.cz, wkk.cz and puttpd.cz, also share IP numbers with zero.cz.
Name Servers
zero.cz uses two name servers for its delegation: ns2.web4u.cz and ns.web4u.cz.
zero.cz shares its NS records with other domains, for example feset.cz, autograbl.cz, 90.91.81.in-addr.arpa and two others.
The two host names ns2.web4u.cz and ns.web4u.cz each have a pair of IP addresses: ns2.web4u.cz has 85.207.53.12 and 2a02:a40:100:28ff::12, and ns.web4u.cz has 185.14.224.241 and 2001:1568:fd::241.
Mail Servers
The sole mail server for zero.cz is mail.zero.cz.
mail.zero.cz directs to just one IP number, 81.91.84.134.