DNS
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.nexo.systems · 23.88.115.137:443

Verified

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

Subject
CN=mail.nexo.systems
Issuer
C=US O=Let's Encrypt CN=YR2
Valid from
2026-09-29T12:54:37+00:00
Expires
2026-12-28T12:54:36+00:00
Days remaining
44
Serial (hex)
06619DB755D89319C56A7548CB9EA7FE3C62
Signature
RSA-SHA256
Public key
RSA 4096

Subject alternative names (SAN)

DNS:autoconfig.justin-harth.de, DNS:autoconfig.nexo.systems, DNS:autodiscover.justin-harth.de, DNS:autodiscover.nexo.systems, DNS:mail.nexo.systems

SHA-256 fingerprint

BF:97:61:F6:A5:F2:DF:11:50:E7:29:41:83:F3:78:AB:AD:B7:0E:56:77:C2:9F:00:93:02:C6:F0:D2:55:84:1C
Certificate extensions & PEM
keyUsage
Digital Signature, Key Encipherment
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
5F:E2:90:88:E5:53:BF:0B:23:30:BA:AE:34:83:68:80:F1:93:20:ED
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:autoconfig.justin-harth.de, DNS:autoconfig.nexo.systems, DNS:autodiscover.justin-harth.de, DNS:autodiscover.nexo.systems, DNS:mail.nexo.systems
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr2.c.lencr.org/99.crl
ct_precert_scts
Signed Certificate Timestamp: Version : v1 (0x0) Log ID : D7:6D:7D:10:D1:A7:F5:77:C2:C7:E9:5F:D7:00:BF:F9: 82:C9:33:5A:65:E1:D0:B3:01:73:17:C0:C8:C5:69:77 Timestamp : Sep 29 13:53:07.638 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:45:02:20:4C:88:97:80:A5:E9:0A:7D:CF:94:27:34: 01:50:94:D2:AD:8B:39:4D:19:54:9C:C7:D5:A7:BE:6A: 09:ED:6A:85:02:21:00:8C:3A:D6:0A:44:60:9F:85:24: F0:CB:94:5F:8F:B2:5E:86:D9:6F:E3:F7:0B:43:11:F2: 77:EF:C2:8E:48:F2:9D 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 29 13:53:08.418 2026 GMT Extensions: 00:00:05:00:46:68:13:4A Signature : ecdsa-with-SHA256 30:44:02:20:39:C8:31:46:39:B3:B2:28:A3:87:00:C5: C6:91:99:8D:C6:B0:18:CB:AB:43:F1:EB:20:56:3F:54: 41:CE:51:7A:02:20:5A:84:27:F6:32:63:2C:13:C1:9E: E3:ED:FB:37:DC:03:46:E7:B1:83:56:D3:B8:5B:96:58: 2F:09:09:6E:7B:0B
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_256_GCM_SHA384 · Checked 2026-11-13T13:36:46+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
659
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
2120
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

Registration / WHOIS →DNS records →