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.

100 hosts (first page) · 296 ms

HostCertsFirst seenLast seenDNS
osstf.ca 6 2025-09-18 2026-10-02 ok
*.osstf.ca 4 2025-08-25 2026-08-27 —
D10.osstf.ca 1 2026-01-08 2026-01-08 —
www.D10.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d10.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
D20.osstf.ca 1 2026-01-08 2026-01-08 —
www.D20.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d20.osstf.ca 1 2026-07-28 2026-07-28 ok
D30.osstf.ca 1 2026-01-08 2026-01-08 —
www.D30.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d30.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
www.d30.osstf.ca 5 2025-09-11 2026-10-04 ok
D01.osstf.ca 1 2026-01-08 2026-01-08 —
www.D01.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d01.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d01.osstf.ca 7 2025-09-11 2026-10-02 nxdomain
D11.osstf.ca 1 2026-01-08 2026-01-08 —
www.D11.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d11.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
D21.osstf.ca 1 2026-01-08 2026-01-08 —
www.D21.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d21.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
D31.osstf.ca 1 2026-01-08 2026-01-08 —
www.D31.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d31.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
autodiscover.d31.u61.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d31.u61.osstf.ca 5 2025-09-11 2026-10-04 ok
D02.osstf.ca 1 2026-01-08 2026-01-08 —
www.D02.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d02.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d02.osstf.ca 5 2025-09-11 2026-10-04 ok
D12.osstf.ca 1 2026-01-08 2026-01-08 —
www.D12.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d12.osstf.ca 1 2026-07-28 2026-07-28 ok
D22.osstf.ca 1 2026-01-08 2026-01-08 —
www.D22.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d22.osstf.ca 1 2026-07-28 2026-07-28 ok
D32.osstf.ca 1 2026-01-08 2026-01-08 —
www.D32.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d32.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
www.d32.osstf.ca 7 2025-09-11 2026-10-02 nodata
D03.osstf.ca 1 2026-01-08 2026-01-08 —
www.D03.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d03.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d03.osstf.ca 5 2025-09-11 2026-10-02 ok
D13.osstf.ca 1 2026-01-08 2026-01-08 —
www.D13.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d13.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d13.osstf.ca 5 2025-09-11 2026-10-04 ok
D23.osstf.ca 1 2026-01-08 2026-01-08 —
www.D23.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d23.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d23.osstf.ca 5 2025-09-11 2026-10-02 ok
D33.osstf.ca 1 2026-01-08 2026-01-08 —
www.D33.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d33.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
www.d33.osstf.ca 5 2025-09-11 2026-10-02 ok
D04.osstf.ca 1 2026-01-08 2026-01-08 —
www.D04.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d04.osstf.ca 1 2026-07-28 2026-07-28 ok
D14.osstf.ca 1 2026-01-08 2026-01-08 —
www.D14.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d14.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
www.d14.osstf.ca 5 2025-09-11 2026-10-02 ok
D24.osstf.ca 1 2026-01-08 2026-01-08 —
www.D24.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d24.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d24.osstf.ca 5 2025-09-11 2026-10-02 ok
D34.osstf.ca 1 2026-01-08 2026-01-08 —
www.D34.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d34.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d34.osstf.ca 5 2025-09-11 2026-10-02 ok
D15.osstf.ca 1 2026-01-08 2026-01-08 —
www.D15.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d15.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
D25.osstf.ca 1 2026-01-08 2026-01-08 —
www.D25.osstf.ca 1 2026-01-08 2026-01-08 —
vpn.d25.osstf.ca 1 2026-01-12 2026-01-12 ok
www.vpn.d25.osstf.ca 1 2026-01-12 2026-01-12 nxdomain
autodiscover.d25.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d25.osstf.ca 5 2025-09-11 2026-10-04 ok
D35.osstf.ca 1 2026-01-08 2026-01-08 —
www.D35.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d35.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
D16.osstf.ca 1 2026-01-08 2026-01-08 —
www.D16.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d16.osstf.ca 1 2026-07-28 2026-07-28 ok
D26.osstf.ca 1 2026-01-08 2026-01-08 —
www.D26.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d26.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d26.osstf.ca 2 2025-10-24 2025-10-24 ok
autodiscover.d33.u66.osstf.ca 1 2026-07-28 2026-07-28 nxdomain
D07.osstf.ca 1 2026-01-08 2026-01-08 —
www.D07.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d07.osstf.ca 1 2026-07-28 2026-07-28 ok
D17.osstf.ca 1 2026-01-08 2026-01-08 —
www.D17.osstf.ca 1 2026-01-08 2026-01-08 —
autodiscover.d17.osstf.ca 1 2026-07-28 2026-07-28 ok
www.d17.osstf.ca 5 2025-09-11 2026-10-02 ok
D27.osstf.ca 1 2026-01-08 2026-01-08 —

Showing the first 100 hostnames — sign in with GitHub or Google to page the full list, or use the API with an API key: GET /v1/hosts/osstf.ca.

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/osstf.ca.