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THE CERTIFICATE BEHIND THE CONNECTION

TLS certificate checker.

Inspect SSL/TLS certificates for any public domain or subdomain.

Checks HTTPS on port 443, including subject alternative names, validity dates and the presented chain.

SSL certificate

TLSv1.3

ifiber.cz · 37.9.175.211:443

Verified

Certificate chain, hostname and dates verified using this server’s CA store.

Subject
CN=ifiber.cz
Issuer
C=US O=Let's Encrypt CN=YR2
Valid from
2026-09-11T13:30:14+00:00
Expires
2026-12-10T13:30:13+00:00
Days remaining
52
Serial (hex)
065700AC96690C979B5D8A6FA620E20E6050
Signature
RSA-SHA256
Public key
RSA 4096

Subject alternative names (SAN)

DNS:ifiber.cz, DNS:www.ifiber.cz

SHA-256 fingerprint

0A:30:21:B8:14:3D:BE:F1:EB:47:D1:CB:08:7F:0A:28:A0:51:FB:BF:89:E8:7A:AD:AF:CC:C4:83:3E:55:C6:EC
Certificate extensions & PEM
keyUsage
Digital Signature, Key Encipherment
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
DF:01:A4:D3:C6:03:DB:43:45:55:55:1D:50:7A:82:53:8D:01:12:37
authorityKeyIdentifier
40:15:2D:26:79:ED:32:20:9E:DF:9A:72:1D:D6:32:1F:81:0C:81:0C
authorityInfoAccess
CA Issuers - URI:http://yr2.i.lencr.org/
subjectAltName
DNS:ifiber.cz, DNS:www.ifiber.cz
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr2.c.lencr.org/81.crl
ct_precert_scts
Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 94:4E:43:87:FA:EC:C1:EF:81:F3:19:24:26:A8:18:65: 01:C7:D3:5F:38:02:01:3F:72:67:7D:55:37:2E:19:D8 Timestamp : Sep 11 14:28:44.212 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:44:02:20:6D:47:C8:61:E7:7C:30:5B:1A:A8:B0:DA: 4C:BC:47:CF:0F:B2:19:B4:0F:E7:C2:E4:F9:12:04:90: B1:19:1D:BD:02:20:00:A0:07:8B:14:5C:92:7E:05:F8: 7F:13:27:97:4A:86:A5:A0:E3:47:15:59:C6:8F:D2:75: 20:82:CD:06:BC:EE Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 46:AF:86:3D:3B:3E:E5:9F:A5:77:DE:A8:24:5D:36:B0: D9:ED:22:A2:23:F4:61:77:41:22:94:52:EE:95:50:5F Timestamp : Sep 11 14:28:44.352 2026 GMT Extensions: 00:00:05:00:2B:64:E0:38 Signature : ecdsa-with-SHA256 30:45:02:21:00:B9:52:74:55:BD:74:5F:DC:40:45:C5: 6A:5F:FC:41:B2:AC:A1:6C:7C:4C:9E:4F:4C:C7:1E:55: 30:6C:D6:99:B9:02:20:3F:53:28:BB:D4:C2:FE:76:52: 07:5D:5A:D9:91:2E:EB:F6:01:9A:F6:63:87:49:12:A2: B4:C0:6B:DC:98:47:57
-----BEGIN CERTIFICATE-----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==
-----END CERTIFICATE-----

Cipher: TLS_AES_128_GCM_SHA256 · Checked 2026-10-19T02:51:44+00:00

Server-presented chain · 2 additional certificates

Chain certificate 1

Subject
C=US O=Let's Encrypt CN=YR2
Issuer
C=US O=ISRG CN=Root YR
Valid from
2025-09-03T00:00:00+00:00
Expires
2028-09-02T23:59:59+00:00
Days remaining
684
Serial (hex)
4EBD24947E24D394802D84A52FD5B319
Signature
RSA-SHA256
Public key
RSA 2048

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

23:8B:85:A0:09:9C:65:B9:70:47:7D:57:24:F1:A1:D4:75:CE:50:58:CF:FE:4E:FA:87:33:89:9B:DB:86:3C:47
Certificate extensions & PEM
keyUsage
Digital Signature, Certificate Sign, CRL Sign
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:TRUE, pathlen:0
subjectKeyIdentifier
40:15:2D:26:79:ED:32:20:9E:DF:9A:72:1D:D6:32:1F:81:0C:81:0C
authorityKeyIdentifier
DE:E7:5B:60:D0:22:6D:40:28:7D:3F:0D:01:FE:A4:B5:52:B4:51:94
authorityInfoAccess
CA Issuers - URI:http://yr.i.lencr.org/
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr.c.lencr.org/ 
-----BEGIN CERTIFICATE-----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==
-----END CERTIFICATE-----

Chain certificate 2

Subject
C=US O=ISRG CN=Root YR
Issuer
C=US O=Internet Security Research Group CN=ISRG Root X1
Valid from
2026-05-13T00:00:00+00:00
Expires
2032-09-02T23:59:59+00:00
Days remaining
2145
Serial (hex)
F24B6D17F9D9AD7CB1C9FEA78782699F
Signature
RSA-SHA256
Public key
RSA 4096

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

07:26:39:D0:B1:40:D5:BF:FA:E1:6A:D9:C3:F6:CC:60:86:04:06:21:F5:1E:E6:1A:6D:46:A8:91:5C:07:CF:76
Certificate extensions & PEM
keyUsage
Certificate Sign, CRL Sign
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:TRUE
subjectKeyIdentifier
DE:E7:5B:60:D0:22:6D:40:28:7D:3F:0D:01:FE:A4:B5:52:B4:51:94
authorityKeyIdentifier
79:B4:59:E6:7B:B6:E5:E4:01:73:80:08:88:C8:1A:58:F6:E9:9B:6E
authorityInfoAccess
CA Issuers - URI:http://x1.i.lencr.org/
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://x1.c.lencr.org/ 
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

One endpoint on port 443. Server-presented chain; no revocation, OCSP, CT or full TLS security scan.

View certificate JSON

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