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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

mail.osso.nl · 91.194.224.40:443

Verified

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

Subject
CN=mail.osso.nl
Issuer
C=US O=Let's Encrypt CN=YR2
Valid from
2026-09-22T19:25:54+00:00
Expires
2026-12-21T19:25:53+00:00
Days remaining
74
Serial (hex)
060D4D0C80E53890B1CEF7D06D135195ED40
Signature
RSA-SHA256
Public key
RSA 2048

Subject alternative names (SAN)

DNS:mail.osso.nl

SHA-256 fingerprint

E1:4F:65:76:23:BA:41:0B:3F:ED:A7:1E:30:0B:E1:B7:F4:EB:EB:65:97:5A:BE:4F:7B:0B:02:DB:D6:2D:10:9E
Certificate extensions & PEM
keyUsage
Digital Signature, Key Encipherment
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
2C:D8:AE:72:72:68:6A:6C:AF:AE:5D:64:B0:40:C5:39:FD:63:75:75
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:mail.osso.nl
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr2.c.lencr.org/65.crl
ct_precert_scts
Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 8E:CA:47:0B:AC:DE:6A:F3:A2:06:B0:A4:7A:84:B7:46: FE:1F:C6:BF:95:3E:25:E6:9B:4E:E4:02:48:F3:C6:E8 Timestamp : Sep 22 20:24:25.861 2026 GMT Extensions: 00:00:05:00:12:93:D5:4B Signature : ecdsa-with-SHA256 30:44:02:20:63:9A:60:F4:59:C7:E4:CC:4A:AA:2D:98: 0B:BB:53:54:F4:84:8F:77:26:CA:DB:3E:FB:A1:CC:1D: 57:F0:94:EB:02:20:32:AA:2B:84:78:C3:B2:79:07:A5: 19:E7:B9:DA:7A:70:3C:F7:B9:F5:06:34:21:76:7F:CE: 59:10:3C:1B:62:E4 Signed Certificate Timestamp: Version : v1 (0x0) Log ID : C8:A3:C4:7F:C7:B3:AD:B9:35:6B:01:3F:6A:7A:12:6D: E3:3A:4E:43:A5:C6:46:F9:97:AD:39:75:99:1D:CF:9A Timestamp : Sep 22 20:24:26.926 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:44:02:20:66:41:5B:CA:D7:08:8D:ED:63:56:34:38: BE:92:7A:0B:4E:4E:92:4B:F7:8B:A4:F2:CD:5E:6D:23: 4D:17:49:7C:02:20:2F:F5:3B:A2:3E:BC:0D:CD:38:13: 67:B6:0E:BC:06:A0:A0:CF:BC:6E:CE:09:C5:35:A2:02: FB:64:39:9A:A8:94
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_256_GCM_SHA384 · Checked 2026-10-08T14:00:26+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
695
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
2156
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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