Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts, first/last seen and live DNS status.

7 hosts · 232 ms

HostCertsFirst seenLast seenDNS
3cx.net 16 2025-11-07 2026-10-04 ok
*.3cx.net 21 2025-11-07 2026-10-04 —
services-dashboard.3cx.net 1 2026-04-17 2026-04-17 ok
testy-tester-prem.3cx.net 2 2026-05-18 2026-05-18 ok
corp.3cx.net 5 2026-04-30 2026-08-28 nodata
*.corp.3cx.net 5 2026-04-30 2026-08-28 —
downloads.3cx.net 5 2026-05-08 2026-09-06 ok

Programmatic access, with DNS A records: API GET /v1/hosts/3cx.net (API key for paging).

Shown here: hostnames with a certificate that is valid now or expired within the last 90 days. The full history since 2013 — hostnames whose last certificate expired earlier — is a Pro plan method: GET /v1/hosts-history/3cx.net.