dns.pizza
Domain Intelligence Report

master.cz

Full ownership history report — $29 at AboutUsCompare
Gathering intelligence... (12/12)
DNS
WHOIS
Security
Email
DNSSEC
Threats
Deliverability
SSL/TLS
HTTP
Tech Stack
Subdomains
Archive
Safe
threat: medium
no attacks or spoofing
Up
HTTP 200
reachable and responding
Right
Set up Page Watch
it is what it is
Ready
87d ahead
you see what's coming
Outline
WHOIS
Webglobe, s.r.o. · registered 28 years ago · expires Oct 5, 2027
DNS
1 A · 2 MX · 3 NS · 4 CAA · 1 PTR · 1 SOA · 6 TXT · 1 AAAA
SSL/TLS
Asseco Data Systems S.A. · TLSv1.3 · expires in 87d · 2 SANs
Email Auth
SPF ✓ · DKIM ✓ · DMARC ✓ (p=reject)
DNSSEC
signed · valid chain of trust
Tech Stack
Host: MasterDC s.r.o. · Email: Self-hosted
HTTP
2 redirect → 200 · HSTS ✓ · CSP ✗ · X-Frame ✓ · Nosniff ✓
Security
B (180/215) · 1 high
Threats
risk: medium
Deliverability
A+ (98/100) · 2 MX · 4 IPs · 1 issue(s)
Subdomains
3 found · 94 answered (18 timed out) — autodiscover, mail, www
Web Archive
first snapshot 1998-12-05 · 27y archived
DNS Recordschecked 7.9d ago
Details
1 A · 2 MX · 3 NS · 4 CAA · 1 PTR · 1 SOA · 6 TXT · 1 AAAA
WHOISchecked 7.9d ago
Details
Webglobe, s.r.o.
Registered 28 years ago
Expires Oct 5, 2027
Renewal history →
Then vs Nownew
No card for this name. We compare then and now for domains that are in the top million and had an AboutUs page. That says nothing about this domain’s age or safety.
Check what it is now →
SSL/TLSchecked 7.9d ago
Details
Valid certificate
Issuer: Asseco Data Systems S.A.
Protocol: TLSv1.3
Expires in 87 days
2 SAN(s)
Securitychecked 7.9d ago
Details
B
180/215
1 high
Weakest: Basic Security, Advanced Security
Email Authchecked 7.9d ago
Details
SPFDKIMDMARC
Policy: reject
DNSSECchecked 7.9d ago
Details
Valid chain of trust
Tech Stackchecked 7.9d ago
Details
MasterDC s.r.o.Email: Self-hostedGoogle Search Console
HTTP / Headerschecked 7.9d ago
Details
2 redirect(s) → 200
HSTSCSPX-FrameNosniff
Threatschecked 7.9d ago
Details
Risk: medium · score 0.6999999999999998
Zone census
Subdomainschecked 7.9d ago
Details
3 found · 94 answered · 18 timed out (unknown)
autodiscovermailwww
Click a subdomain for its full report
Web Archivechecked 7.9d ago
Details
First archived: 1998-12-05
~27 years of history
Deliverabilitychecked 7.9d ago
Details
A+
98/100 · 1 issue(s)
2 MX · 4 IP(s)

IPv6

Measured 2026-11-04 18:37 UTC · aaaa.bot
A

Website, mail and DNS all work over IPv6.

The published IPv6 address accepted a connection when we tried it.

  • ✓ master.cz answers (1 of 1 addresses)
  • ✓ www.master.cz answers (1 of 1)
  • ✓ Mail: 2 of 2 servers have IPv6
  • ✓ Nameservers: 3 of 3 have IPv6
Details: published addresses and what answered

Loads over IPv6 with a valid certificate after 1 redirect: HTTP 200.

master.czPublished2a01:430:100:2b::5Answers when we connect✓ answers on 443
www.master.czPublished2a01:430:100:2b::5Answers when we connect✓ answers on 443
MailPublishedmail.master.czns3.master.czAnswers when we connect✓ has IPv6✓ has IPv6
NameserversPublishedns1.master.czns2.master.czns3.master.czAnswers when we connect✓ has IPv6✓ has IPv6✓ has IPv6
First measured with IPv6 on 2026-11-04Changes are recorded from here on, each with its date.
Full check on aaaa.bot →Permanent receipt yFEMQKt9pDJSON

Lineage

Our records: Jun 2, 2009 → Nov 4, 2026

Oldest registry snapshot we hold: 2025 · 1 renewal on record. These dates are when our records begin, not when the domain was registered.

DNS provider

  • master.cz
    Jun 2009 – Jun 2026

IPv6

  • IPv6published, and answering
    First measured Nov 2026
What changed
  1. IPv6 first measured: published, and answering on Nov 4, 2026master.cz has 1 IPv6 address. Grade A. Measured by aaaa.bot, 2026-11-04 18:37 UTC. No earlier IPv6 record is held, so this is not a "gained" date.
  2. Renewed +1 year between Aug 10, 2025 and Sep 11, 2025Expiry moved from 2025-10-05 to 2026-10-05.

Solid bar: the stretch we observed that name. Dot: a single sighting. Dotted line: no record between sightings of the same name. Nothing is drawn between different names.

Registrar and renewals: 14 WHOIS/RDAP snapshots, 2025-02-09 to 2026-04-21 (ledger built 2026-09-27). Every renewal

DNS provider, WHOIS snapshots: 99 WHOIS/RDAP snapshots that listed nameservers, 2009-06-02 to 2026-06-12 (who.is archive). Both sources feed one row per provider (hover a bar to see which); a change is placed between the nearest observations on either side, and where the two sources disagree, both are listed under What changed.

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Explore related

Registered in 1998 — the same year as sharepoint.com, mozilla.org and medium.com.

AgeDomains from 1998TLD.cz domainsRegistrarWebglobe, s.r.o.IPv6Does master.cz have IPv6?