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

mail01.fnmuc.net · 116.202.11.8:443

Verified

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

Subject
CN=imap.fnmuc.net
Issuer
C=US O=Let's Encrypt CN=YR1
Valid from
2026-10-08T14:20:02+00:00
Expires
2027-01-06T14:20:01+00:00
Days remaining
71
Serial (hex)
06E655574889A84F47D778EB608D8F764C50
Signature
RSA-SHA256
Public key
RSA 4096

Subject alternative names (SAN)

DNS:imap.fnmuc.net, DNS:mail01-v4.fnmuc.net, DNS:mail01.fnmuc.net, DNS:smtp.fnmuc.net, DNS:webmail.fnmuc.net, DNS:webmail.mail01.fnmuc.net

SHA-256 fingerprint

19:9E:C2:CB:6F:03:54:EA:26:74:C8:25:96:F5:9E:5F:E6:B1:94:D6:69:CA:6F:D9:D7:E7:36:55:A5:96:22:9D
Certificate extensions & PEM
keyUsage
Digital Signature, Key Encipherment
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
FF:6E:F2:E6:5F:65:24:DE:4D:8A:5D:2E:72:DC:67:06:B9:33:01:B1
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:imap.fnmuc.net, DNS:mail01-v4.fnmuc.net, DNS:mail01.fnmuc.net, DNS:smtp.fnmuc.net, DNS:webmail.fnmuc.net, DNS:webmail.mail01.fnmuc.net
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr1.c.lencr.org/81.crl
ct_precert_scts
Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 44:C2:BD:0C:E9:14:0E:64:A5:C9:4A:01:93:0A:5A:A1: BB:35:97:0E:00:EE:11:16:89:68:2A:1C:44:D7:B5:66 Timestamp : Oct 8 15:18:32.996 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:44:02:20:72:82:3F:71:36:33:C4:F3:AA:D3:82:DB: 67:1A:2A:BA:39:AD:E3:77:AA:2E:9B:39:1E:25:25:79: 99:45:18:78:02:20:2E:5B:01:70:59:AD:17:CB:D9:0D: 33:2C:D0:85:1F:8F:C2:C0:F9:8B:DF:E9:E0:F6:4E:84: 19:6E:AE:73:F9:C9 Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 44:E8:22:FC:2B:AB:0E:92:EE:D0:E9:FA:D6:96:64:60: 27:76:D0:17:60:E0:89:05:09:C9:23:A1:B0:3F:C3:7F Timestamp : Oct 8 15:18:30.133 2026 GMT Extensions: 00:00:05:00:08:16:D0:65 Signature : ecdsa-with-SHA256 30:44:02:20:6B:6E:79:FF:D2:B9:C2:DB:66:C4:D7:45: DF:74:07:BA:F4:C2:2B:63:F2:FD:2D:E9:0A:68:22:F6: 96:C2:9E:48:02:20:3D:B1:19:80:45:EE:D4:43:D9:62: AB:FA:83:61:68:15:B7:C5:6A:38:CE:F7:E6:A6:E6:CA: 2A:88:68:9C:A4:92
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_128_GCM_SHA256 · Checked 2026-10-27T10:58:16+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
676
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
2137
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 →