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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

mailgate.steffann.nl · 185.54.92.29:443

Verified

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

Subject
CN=mailgate.steffann.nl
Issuer
C=US O=Let's Encrypt CN=YR1
Valid from
2026-09-20T22:22:41+00:00
Expires
2026-12-19T22:22:40+00:00
Days remaining
70
Serial (hex)
0572626176A887CB365A27B896D93CBE52F8
Signature
RSA-SHA256
Public key
RSA 4096

Subject alternative names (SAN)

DNS:mailgate.steffann.nl

SHA-256 fingerprint

E8:DA:0C:5B:80:C0:B6:B5:C0:42:09:C7:AA:88:88:C7:BA:2F:4F:84:50:90:63:2A:3F:0E:6E:A8:ED:FB:B6:20
Certificate extensions & PEM
keyUsage
Digital Signature, Key Encipherment
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
F5:A0:A9:D1:FC:9F:80:21:18:9D:AD:32:45:68:36:21:96:95:79:BD
authorityKeyIdentifier
1F:2F:35:BE:46:14:82:CD:40:B1:AE:79:2C:55:78:FA:F7:D4:68:FB
authorityInfoAccess
CA Issuers - URI:http://yr1.i.lencr.org/
subjectAltName
DNS:mailgate.steffann.nl
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr1.c.lencr.org/121.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 : Sep 20 23:21:11.652 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:44:02:20:5D:6B:1A:7A:D7:F3:77:0A:C6:BD:EE:B4: 4B:C8:C3:5B:C7:67:6B:15:4D:42:E7:FF:E2:1D:0A:85: E1:0E:EC:18:02:20:6B:28:7E:A1:F7:00:91:D7:F4:6A: 37:40:EF:BC:AE:F8:A7:E0:5A:60:85:7A:E2:58:67:3D: 68:57:1B:C4:A6:87 Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 1A:8B:9D:6B:0F:FE:BF:81:B4:79:39:C6:D2:31:0A:86: D6:D1:02:D4:F0:46:E2:18:2C:9D:E3:5F:5E:26:25:EF Timestamp : Sep 20 23:21:12.364 2026 GMT Extensions: 00:00:05:00:43:5F:A9:39 Signature : ecdsa-with-SHA256 30:45:02:21:00:B4:61:49:48:A6:1E:DE:24:D4:63:91: 8E:C7:EF:97:ED:37:3D:B2:71:A0:1B:16:CE:40:70:20: DB:48:B5:59:1B:02:20:7D:60:3E:38:47:7E:FA:91:D2: 72:A2:0C:CC:47:FE:E4:31:3B:F7:E2:44:4E:8E:BC:1C: 25:58:05:BA:D6:A4:52
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_128_GCM_SHA256 · Checked 2026-10-10T17:32:42+00:00

Server-presented chain · 2 additional certificates

Chain certificate 1

Subject
C=US O=Let's Encrypt CN=YR1
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
693
Serial (hex)
A20253F15F2691C05DC1CE13B9BCCA4E
Signature
RSA-SHA256
Public key
RSA 2048

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

13:94:96:34:D9:9C:D6:FD:6A:A8:0B:C0:34:FE:FA:CC:EB:19:69:FE:EF:98:65:86:71:3E:CD:BB:05:75:8D:3F
Certificate extensions & PEM
keyUsage
Digital Signature, Certificate Sign, CRL Sign
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:TRUE, pathlen:0
subjectKeyIdentifier
1F:2F:35:BE:46:14:82:CD:40:B1:AE:79:2C:55:78:FA:F7:D4:68:FB
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
2154
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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