21st · Domain Security

21St Domain Security

Domain security

Domain security posture for 21st, probed live across 1 host(s) and 1 registrable domain(s). 1 host(s) serve HTTPS (up to TLSv1.3); 1 advertise HSTS. Email/DNS controls: DNSSEC absent, SPF present, DMARC present (p=reject).

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Transport & Host Security

21st.dev
HTTPS: yes · TLS: TLSv1.3 · HSTS: yes · cert expires: Sep 28 00:24:27 2026 GMT

Domain (DNS/Email) Security

21st.dev
DNSSEC: no · SPF: yes · DMARC: yes (p=reject) · CAA: yes

Source

Domain Security

21st-domain-security.yml Raw ↑ 
generated: '2026-07-17'
method: probed
source: live DNS/TLS/HTTP probes of apis.yml + OpenAPI hosts
hosts:
- host: 21st.dev
  https: true
  tls_version: TLSv1.3
  cert_expires: Sep 28 00:24:27 2026 GMT
  hsts: true
  hsts_max_age: 63072000
domains:
- domain: 21st.dev
  dnssec: false
  caa:
  - 0 issue "ssl.com"
  - 0 issuewild "comodoca.com"
  - 0 issuewild "digicert.com; cansignhttpexchanges=yes"
  - 0 issuewild "letsencrypt.org"
  - 0 issuewild "pki.goog; cansignhttpexchanges=yes"
  - 0 issuewild "ssl.com"
  spf: true
  dmarc: true
  dmarc_policy: reject