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 cantr.org

Self-signed
Issued by (CA)
ExampleCorp
Subject
*.example.com
Valid from
Oct 24, 2016
Valid until
Oct 24, 2017 (expired 3240 days ago)
Public key
RSA 2048-bit
Serial
90064253260B4932
SHA-256 fingerprint
22:6B:24:AA:15:2B:EE:63:B6:53:6E:0F:5A:91:16:78:99:8D:61:8B:B3:CB:37:97:BF:9B:73:84:01:F1:E4:58
Chain
*.example.com

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 Aug 7, 2026.

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Uptime

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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.

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