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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

ostnet.pl · 62.133.128.105:443

Verified
The certificate expires within 30 days.

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

Subject
CN=ostnet.pl
Issuer
C=US O=Let's Encrypt CN=YE2
Valid from
2026-07-29T21:16:35+00:00
Expires
2026-10-27T21:16:34+00:00
Days remaining
25
Serial (hex)
05F78BEE3EC8E379A3E5BA51089C8210B704
Signature
ecdsa-with-SHA384
Public key
EC 256 prime256v1

Subject alternative names (SAN)

DNS:ostnet.pl

SHA-256 fingerprint

B9:3B:6C:D5:BF:20:E4:39:64:E6:BA:DD:AE:23:2B:20:11:DE:D1:89:01:06:1C:E9:5D:8F:5B:C6:74:92:F6:62
Certificate extensions & PEM
keyUsage
Digital Signature
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
02:B1:05:81:A6:01:41:2C:AD:C5:54:8C:5B:49:B8:8D:14:66:E0:7B
authorityKeyIdentifier
B9:59:F2:8E:CF:22:F0:86:D3:37:48:FF:76:14:18:BA:82:D8:55:87
authorityInfoAccess
CA Issuers - URI:http://ye2.i.lencr.org/
subjectAltName
DNS:ostnet.pl
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://ye2.c.lencr.org/5.crl
ct_precert_scts
Signed Certificate Timestamp: Version : v1 (0x0) Log ID : CB:38:F7:15:89:7C:84:A1:44:5F:5B:C1:DD:FB:C9:6E: F2:9A:59:CD:47:0A:69:05:85:B0:CB:14:C3:14:58:E7 Timestamp : Jul 29 22:15:05.548 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:45:02:21:00:A0:02:96:68:17:47:CF:2F:19:3F:91: 5A:2B:95:C5:56:1C:5E:9C:67:6A:E6:A8:B3:5D:71:6B: 71:9B:D8:8B:3D:02:20:21:29:6A:01:58:EF:D1:46:15: F9:83:C0:F0:2C:4D:C9:75:F5:95:CC:3E:C9:13:76:52: F4:6D:FB:00:04:EE:C9 Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 26:E3:64:6E:58:69:21:23:BC:34:3F:47:24:35:9B:37: 92:CD:24:5A:88:D8:15:D3:93:33:FD:99:18:AB:47:23 Timestamp : Jul 29 22:15:04.555 2026 GMT Extensions: 00:00:05:00:2E:DC:2A:3C Signature : ecdsa-with-SHA256 30:44:02:20:72:79:45:C8:52:47:11:07:26:77:32:D1: CE:4F:E3:07:C0:AF:11:E2:5D:8A:F3:5E:9F:C0:F8:E0: 7E:82:E3:9A:02:20:44:6D:86:D0:7E:47:81:0A:6D:07: B0:F3:20:DE:69:60:8F:CC:0D:70:3C:7B:07:42:80:40: 89:AD:19:47:81:E4
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_128_GCM_SHA256 · Checked 2026-10-02T00:27:17+00:00

Server-presented chain · 3 additional certificates

Chain certificate 1

Subject
C=US O=Let's Encrypt CN=YE2
Issuer
C=US O=ISRG CN=Root YE
Valid from
2025-09-03T00:00:00+00:00
Expires
2028-09-02T23:59:59+00:00
Days remaining
701
Serial (hex)
4DF3B15DD6C0784C507CD37B58E6F115
Signature
ecdsa-with-SHA384
Public key
EC 384 secp384r1

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

97:65:8D:E8:C6:8D:FA:98:AC:E1:E5:02:8A:63:D5:4A:1A:AE:91:1B:3E:21:47:10:76:C6:85:0C:D0:8C:BA:B4
Certificate extensions & PEM
keyUsage
Digital Signature, Certificate Sign, CRL Sign
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:TRUE, pathlen:0
subjectKeyIdentifier
B9:59:F2:8E:CF:22:F0:86:D3:37:48:FF:76:14:18:BA:82:D8:55:87
authorityKeyIdentifier
A3:C8:26:5A:8E:A1:4C:D0:35:63:FC:9B:23:C8:3A:AE:56:F3:4F:56
authorityInfoAccess
CA Issuers - URI:http://ye.i.lencr.org/
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://ye.c.lencr.org/ 
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Chain certificate 2

Subject
C=US O=ISRG CN=Root YE
Issuer
C=US O=Internet Security Research Group CN=ISRG Root X2
Valid from
2026-05-13T00:00:00+00:00
Expires
2032-09-02T23:59:59+00:00
Days remaining
2162
Serial (hex)
872165FC34B6E5FBA8ADD5B3705FB53A
Signature
ecdsa-with-SHA384
Public key
EC 384 secp384r1

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

0F:C0:90:1C:CA:2B:AE:9E:9F:DB:B0:2D:50:D0:2F:10:94:F7:B3:66:72:08:69:91:B9:E8:97:62:6D:C4:85:F0
Certificate extensions & PEM
keyUsage
Certificate Sign, CRL Sign
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:TRUE
subjectKeyIdentifier
A3:C8:26:5A:8E:A1:4C:D0:35:63:FC:9B:23:C8:3A:AE:56:F3:4F:56
authorityKeyIdentifier
7C:42:96:AE:DE:4B:48:3B:FA:92:F8:9E:8C:CF:6D:8B:A9:72:37:95
authorityInfoAccess
CA Issuers - URI:http://x2.i.lencr.org/
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://x2.c.lencr.org/ 
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Chain certificate 3

Subject
C=US O=Internet Security Research Group CN=ISRG Root X2
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
2162
Serial (hex)
6C8F1DC727C7117F7BAF853AC980F9CD
Signature
RSA-SHA256
Public key
EC 384 secp384r1

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

EE:5F:7A:BD:69:81:BB:02:55:63:2C:D8:F4:92:83:45:1B:4B:18:84:4D:12:04:0B:44:EE:00:F0:7B:8F:E2:C6
Certificate extensions & PEM
keyUsage
Certificate Sign, CRL Sign
extendedKeyUsage
TLS Web Server Authentication, TLS Web Client Authentication
basicConstraints
CA:TRUE
subjectKeyIdentifier
7C:42:96:AE:DE:4B:48:3B:FA:92:F8:9E:8C:CF:6D:8B:A9:72:37:95
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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