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.

4 hosts · 342 ms

HostCertsFirst seenLast seenDNS
cloud.mail.viatrisconnect.com 2 2025-08-03 2026-07-24 ok
image.mail.viatrisconnect.com 4 2025-09-13 2026-10-01 ok
click.mail.viatrisconnect.com 2 2025-08-03 2026-07-21 ok
view.mail.viatrisconnect.com 2 2025-08-03 2026-07-22 ok

Programmatic access, with DNS A records: API GET /v1/hosts/mail.viatrisconnect.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/mail.viatrisconnect.com.