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

relay.itself.cz · 212.96.161.8:443

Unverified
Certificate verification failed. These are unverified certificate details presented by the server. Peer certificate subjectAltName did not match expected name `relay.itself.cz'

Certificate verification failed

Subject
CN=mail.itself.cz
Issuer
C=US O=Let's Encrypt CN=YR2
Valid from
2026-09-23T00:14:25+00:00
Expires
2026-12-22T00:14:24+00:00
Days remaining
67
Serial (hex)
05F2635FA425114E236F39A742B1C03F3B6C
Signature
RSA-SHA256
Public key
RSA 2048

Subject alternative names (SAN)

DNS:mail.itself.cz

SHA-256 fingerprint

D7:53:AE:94:38:24:3D:82:EA:26:B5:1B:44:7A:D7:31:E4:DB:B1:88:4F:9A:50:75:26:6A:84:AE:AF:D3:F2:5B
Certificate extensions & PEM
keyUsage
Digital Signature, Key Encipherment
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
02:AB:8D:63:E0:BA:C2:21:29:8E:06:84:D8:A4:1D:B7:8A:34:18:AA
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.itself.cz
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr2.c.lencr.org/109.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 23 01:12:55.353 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:44:02:20:68:A4:73:15:2B:E7:66:6C:2D:F8:CD:86: 6A:F3:81:A2:EC:BD:7A:8C:02:9C:6A:C3:E5:FB:C5:EC: 7C:5E:2B:C2:02:20:30:F6:19:11:55:61:B8:EB:4D:71: 5B:F7:61:06:96:2D:20:F9:A5:A3:17:25:AA:AA:6C:1C: 9B:C0:A9:F6:D2:D5 Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 46:AF:86:3D:3B:3E:E5:9F:A5:77:DE:A8:24:5D:36:B0: D9:ED:22:A2:23:F4:61:77:41:22:94:52:EE:95:50:5F Timestamp : Sep 23 01:12:55.535 2026 GMT Extensions: 00:00:05:00:34:03:23:4B Signature : ecdsa-with-SHA256 30:44:02:20:18:08:82:01:88:9A:FE:61:63:A3:63:85: E6:45:33:2B:A1:FB:8A:B8:91:46:3F:8E:AC:AD:5D:33: 7E:8F:B1:3E:02:20:4B:9F:55:42:93:FA:9E:09:F5:14: 33:82:9B:BB:CB:A2:4C:6A:2A:51:9C:44:CD:DB:5D:D3: 3F:A5:1C:F2:08:50
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_128_GCM_SHA256 · Checked 2026-10-15T23:22:24+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
688
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
2149
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-----
MIIF9DCCA9ygAwIBAgIRAPJLbRf52a18scn+p4eCaZ8wDQYJKoZIhvcNAQELBQAw
TzELMAkGA1UEBhMCVVMxKTAnBgNVBAoTIEludGVybmV0IFNlY3VyaXR5IFJlc2Vh
cmNoIEdyb3VwMRUwEwYDVQQDEwxJU1JHIFJvb3QgWDEwHhcNMjYwNTEzMDAwMDAw
WhcNMzIwOTAyMjM1OTU5WjAuMQswCQYDVQQGEwJVUzENMAsGA1UEChMESVNSRzEQ
MA4GA1UEAxMHUm9vdCBZUjCCAiIwDQYJKoZIhvcNAQEBBQADggIPADCCAgoCggIB
ANvGJnN78CTJdWL3+eGfsLN5TrNBJs+VH9hRXqRbwxu9sGNiB0BD1fcOxbSUQCJI
M1xE13Db+5Cw1w0s0EBYsvuIP/6joF0w8cuImbgR1OGgYbSQ4OpzI+DG8SGuTlcE
873OCS+kh3srlo6vl43M5OJg4Aeo1sfHp6kTJDoIiFBNJAY+OKfX/FUvYKuhjT+n
o49lmqmupSBI5PkBQiqrEGtWU5uxU/cQWHGu8jSjFBznZqvbNPLMXMLFxCb3WTfr
JBXXjqvWG+v4bjzxjjeAtOlU7qarRDvNOyAuQYLln904M+faKx8hnLCpJ15ZqaEg
cNlY+9MMWcC5yvL2A2j3l9+2buggZX+dOE91zYmIdawTvSZuVvlbRrAlLxIB6pwM
BjneXCjYQ8+3BCCjssbSNpZU3hTcBDdhfAlEDlYr6pEatnMdmDT5BqnKC92bd0Eh
M1fbLHioLccLCuievT8ZkPhZrq7Mii7gNXAcUEAR8+lzYal+9zTg7C5DALyVOeG/
CqfRAMn1KSHCR0NSA6P8tn/mGRlnCct5rtVCLnVySVpU6H1qGg3DgTOuskf8eahT
MiYbI5ezPJmO5ertalskQ1utp74+eDy92PI4ftHKTbq9IWhH4YZKh3WnJEIt+oQv
lYZbY8tpEroKrFB6PFGzrJIDRyts4HqvuH52RFj2zv/BAgMBAAGjgeswgegwDgYD
VR0PAQH/BAQDAgEGMBMGA1UdJQQMMAoGCCsGAQUFBwMBMA8GA1UdEwEB/wQFMAMB
Af8wHQYDVR0OBBYEFN7nW2DQIm1AKH0/DQH+pLVStFGUMB8GA1UdIwQYMBaAFHm0
WeZ7tuXkAXOACIjIGlj26ZtuMDIGCCsGAQUFBwEBBCYwJDAiBggrBgEFBQcwAoYW
aHR0cDovL3gxLmkubGVuY3Iub3JnLzATBgNVHSAEDDAKMAgGBmeBDAECATAnBgNV
HR8EIDAeMBygGqAYhhZodHRwOi8veDEuYy5sZW5jci5vcmcvMA0GCSqGSIb3DQEB
CwUAA4ICAQA8spSI95KKfn2W6GMmDpHBJSPaLbsS3W93cijJCRCYAc1fsJgL1FIL
7C0C9ecPOdcwB2fi0Dk2p94j9iTJCxmt5CFSKLRWwnXT2MMSXexVxqoVB79BdWPx
VXETkVme/qYSAuKVHh5Ps+5BixgmwS1JkjSAc+MfrUbNssVEEnH0aEiAh+rotXAV
JSP/Ye7LJPEwD9DWG72vVWbhAcuOf5OLjz57Ctk7MgQHynZ7+PlHJtajroCaIbtC
r6tcZZaAwUQm+jQyeWdV+2hv9deOYFmKeQyjjcSrN5Nadrw+L9DZJLbA1HqeNvLh
BgqpP0fvJq2N6EtD574N6eMI7uMsJTnji2UDz9el5XLSv9fqJMuDQtYVb2oTNoKp
oUqhxPVC0aq4eG5MESaIdn8b5ZGSSeAJLMHXljEdlNza+ncfkviXk1POLnnFdvx8
/gk6M374WbLWFXw8N141B/Rl/tINGfl1TxOIiqtiMYkL02RSGb1kq34BL9NPP27z
RGMuHGnzS3hFIrRTfKxrzUZ9RzQWzEG3K6fJ3r2nqSltkeytis9DIBoFY9VmVyjL
M71DMi+y1+TRSJVClEMwvA4yL++7q9XZx5r5wBRWB4kQTKH5qyoZnDw7iiuh1lID
yDFx8r7i9vIJU5HS3moZLkYWAOilMaV9N56A9Bgb6dNcHkvg3NoaYA==
-----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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