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 negima.jp

Self-signed
Issued by (CA)
Dummy
Subject
dummy.local
Valid from
Feb 4, 2026
Valid until
Feb 2, 2036 (3481 days remaining)
Public key
RSA 2048-bit
Serial
9D9AFB5585212873
SHA-256 fingerprint
C4:4B:09:7D:CB:C8:C2:DD:E8:8C:99:1A:78:E5:CC:60:FD:38:6A:C1:AB:CF:F6:4F:B6:AE:42:69:64:4C:2A:3F
Chain
dummy.local

Certificate Authority Authorization (CAA)

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

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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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