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.

26 hosts · 360 ms

HostCertsFirst seenLast seenDNS
k3s.com 31 2026-03-25 2026-10-02 ok
*.k3s.com 23 2026-03-25 2026-10-02 —
argilla.k3s.com 5 2026-05-10 2026-09-08 ok
lyric.k3s.com 5 2026-05-16 2026-09-13 ok
buyinggame.k3s.com 12 2026-04-29 2026-06-27 ok
restore.k3s.com 8 2026-05-04 2026-07-02 ok
aionibmi.k3s.com 2 2026-05-07 2026-05-07 ok
webui.k3s.com 5 2026-05-17 2026-09-15 ok
technical.k3s.com 4 2026-04-23 2026-06-22 ok
lwmail.k3s.com 5 2026-05-02 2026-08-30 ok
anythingllm.k3s.com 5 2026-05-18 2026-09-16 ok
ospm.k3s.com 4 2026-04-21 2026-08-19 ok
fortigatevm.k3s.com 5 2026-05-21 2026-09-19 ok
conan.k3s.com 2 2026-09-09 2026-09-10 ok
info.k3s.com 8 2026-05-21 2026-09-16 ok
odbcphp.k3s.com 5 2026-04-26 2026-08-24 ok
sftp.k3s.com 3 2026-06-15 2026-08-30 ok
portainer.k3s.com 5 2026-05-26 2026-09-24 ok
dcmtools.k3s.com 4 2026-04-28 2026-06-28 ok
fortinet.k3s.com 4 2026-04-22 2026-06-21 ok
superset.k3s.com 4 2026-04-17 2026-08-15 ok
chatbot.k3s.com 5 2026-05-17 2026-09-15 ok
support.k3s.com 5 2026-05-23 2026-09-20 ok
u.k3s.com 10 2026-05-02 2026-08-28 ok
www.k3s.com 12 2026-05-22 2026-09-18 ok
university.k3s.com 19 2026-04-29 2026-08-30 ok

Programmatic access, with DNS A records: API GET /v1/hosts/k3s.com (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/k3s.com.