SSL/TLS Certificate Lookup
Check a domain's SSL/TLS certificate — who issued it, when it expires, and whether the chain is trusted
def-it.com
SSL/TLS Certificate
SSL/TLS Certificate for def-it.com
Valid- Issued by (CA)
- Let's Encrypt
- Subject
- *.def-it.com
- Valid from
- Jul 27, 2026
- Valid until
- Oct 25, 2026 (74 days remaining)
- Public key
- RSA 2048-bit
- Serial
- 0583B36EE0B06498D9D606C21BFB9669B8EF
- SHA-256 fingerprint
- 37:0E:32:82:EF:3D:04:8C:5A:A3:4C:DA:CA:28:65:99:DC:16:2A:47:26:1B:09:94:43:ED:B1:66:41:E5:10:12
- Chain
- YR1 → Root YR → ISRG Root X1
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 6, 2026.
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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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