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.

15 hosts · 257 ms

HostCertsFirst seenLast seenDNS
ulstersavings.com 23 2026-05-07 2026-10-04 ok
*.ulstersavings.com 23 2026-05-07 2026-10-04 —
vdi-connect-01.ulstersavings.com 3 2026-05-21 2026-07-30 nxdomain
usb-prolog-p01.ulstersavings.com 1 2026-05-13 2026-05-13 nxdomain
vdi-connect-02.ulstersavings.com 1 2026-05-13 2026-05-13 nxdomain
kb.ulstersavings.com 4 2026-04-10 2026-08-07 ok
itkb.ulstersavings.com 4 2026-04-15 2026-08-13 ok
prologue.ulstersavings.com 1 2026-05-13 2026-05-13 nxdomain
marketing.ulstersavings.com 3 2026-07-30 2026-07-30 nxdomain
info.ulstersavings.com 1 2026-01-21 2026-01-21 ok
help.ulstersavings.com 4 2026-04-15 2026-08-13 ok
es.ulstersavings.com 5 2026-06-01 2026-09-29 ok
documents.ulstersavings.com 1 2026-05-13 2026-05-13 nxdomain
usb-pws.ulstersavings.com 1 2026-05-13 2026-05-13 nxdomain
test-naut.ulstersavings.com 1 2026-05-13 2026-05-13 nxdomain

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