SSL/TLS Certificate Lookup

Check a domain's SSL/TLS certificate — who issued it, when it expires, and whether the chain is trusted

SSL/TLS Certificate for dcentral-lab.org

Hostname mismatch
Issued by (CA)
Let's Encrypt
Subject
dei.rnl.tecnico.ulisboa.pt
Valid from
Aug 9, 2026
Valid until
Nov 7, 2026 (59 days remaining)
Public key
EC 256-bit
Serial
06C44CEDB70732561C0BADD96645E1250D82
SHA-256 fingerprint
CA:C7:CD:50:F9:A7:53:3A:31:72:EA:35:69:EC:14:02:00:45:24:F7:30:A2:B1:8F:0A:F2:7B:0C:00:38:9A:A8
Chain
YE2 → Root YE → ISRG Root X2 → ISRG Root X1
Subject Alternative Names (1)
dei.rnl.tecnico.ulisboa.pt

Certificate Authority Authorization (CAA)

No CAA policy is published for this domain — any certificate authority may issue for it.

This certificate has been served since Sep 7, 2026.

Never get surprised by dcentral-lab.org's certificate expiring

This is today's certificate. Turn on monitoring and we'll watch dcentral-lab.org continuously, notifying you the moment anything moves across all three signals:

Uptime

We visit the site from multiple regions worldwide and email you within minutes if it goes down, with a per-region breakdown so a real outage stands out from a regional blip.

DNS changes

We watch NS, MX, CAA, DNSSEC, CNAME and A/AAAA records, and identify the host, network, and ASN behind them, so a real migration or hijack stands out from routine noise.

TLS certificate

We warn you 30, 14, 7, and 1 days before it expires, and flag it if the issuing authority changes or the certificate is unexpectedly replaced.

Monitor this certificate free

Free for your first domain: uptime, DNS, and certificate together. No credit card.