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.

24 hosts · 340 ms

HostCertsFirst seenLast seenDNS
du.co 14 2025-08-20 2026-09-06 ok
*.du.co 3 2025-08-20 2025-08-22 —
dashboard.du.co 5 2026-04-10 2026-09-21 ok
service.du.co 2 2025-09-08 2026-08-09 ok
jira.service.du.co 2 2025-09-08 2026-08-09 ok
groove.du.co 4 2026-04-12 2026-08-10 ok
blog.du.co 18 2026-05-22 2026-09-17 ok
1pscim.du.co 31 2026-05-01 2026-10-04 ok
panopticon.du.co 3 2026-05-05 2026-08-20 ok
vpn.du.co 1 2026-02-06 2026-02-06 ok
*.aidp.du.co 20 2026-05-29 2026-09-26 —
kbc.aidp.du.co 5 2026-05-24 2026-09-21 ok
crelan.aidp.du.co 5 2026-05-24 2026-09-21 ok
app.aidp.du.co 5 2026-05-24 2026-09-21 ok
uat.aidp.du.co 5 2026-05-18 2026-09-15 ok
kbc-uat.aidp.du.co 5 2026-05-18 2026-09-15 ok
crelan-uat.aidp.du.co 5 2026-05-18 2026-09-15 ok
test.aidp.du.co 5 2026-05-29 2026-09-26 nxdomain
dev.aidp.du.co 5 2026-05-18 2026-09-15 ok
mta-sts.du.co 4 2026-04-18 2026-08-16 ok
intranet.du.co 6 2026-04-13 2026-09-24 ok
content.du.co 12 2026-05-21 2026-09-16 ok
support.du.co 5 2026-05-09 2026-09-06 ok
www.du.co 17 2026-05-06 2026-09-06 ok

Programmatic access, with DNS A records: API GET /v1/hosts/du.co (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/du.co.