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.

11 hosts · 373 ms

HostCertsFirst seenLast seenDNS
horde.no 7 2026-02-26 2026-09-15 ok
*.horde.no 5 2026-05-18 2026-09-15 —
mail2.horde.no 2 2026-03-01 2026-07-11 ok
20129139.horde.no 3 2026-03-01 2026-07-11 ok
kestrel.horde.no 1 2026-09-03 2026-09-03 nodata
mail.horde.no 2 2026-03-01 2026-07-11 ok
regn.horde.no 1 2026-09-29 2026-09-29 nodata
app.horde.no 10 2026-04-19 2026-08-15 ok
reports.horde.no 2 2026-02-12 2026-07-06 ok
t.horde.no 4 2026-05-06 2026-09-15 ok
slett.horde.no 1 2026-06-03 2026-06-03 nxdomain

Programmatic access, with DNS A records: API GET /v1/hosts/horde.no (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/horde.no.