SSL/TLS Certificate Lookup
Check a domain's SSL/TLS certificate — who issued it, when it expires, and whether the chain is trusted
uni-koeln.nrw
SSL/TLS Certificate
SSL/TLS Certificate for uni-koeln.nrw
Valid- Issued by (CA)
- Let's Encrypt
- Subject
- uni.koeln
- Valid from
- Sep 23, 2026
- Valid until
- Dec 22, 2026 (89 days remaining)
- Public key
- EC 384-bit
- Serial
- 06AAA7EB95D82B3C476D30E15440368E1E8C
- SHA-256 fingerprint
- 34:EE:1E:20:95:8C:4F:CA:C2:C0:BE:69:37:64:00:0C:5B:3E:F7:8A:C4:24:1A:C2:CA:5B:5B:04:BC:57:E2:DA
- Chain
- YE2 → Root YE → ISRG Root X2 → ISRG Root X1
Certificate Authority Authorization (CAA)
No CAA policy is published for this domain — any certificate authority may issue for it.
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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.
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