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

gda.pl · 153.19.250.251:443

Unverified
Certificate verification failed. These are unverified certificate details presented by the server. Peer certificate CN=`dns.gda.pl' did not match expected CN=`gda.pl'

Certificate verification failed

Subject
C=PL ST=pomorskie L=Gdańsk O=Politechnika Gdańska CN=dns.gda.pl
Issuer
C=GR O=Hellenic Academic and Research Institutions CA CN=GEANT TLS ECC 1
Valid from
2026-07-23T04:34:20+00:00
Expires
2027-02-07T04:34:19+00:00
Days remaining
133
Serial (hex)
3F957B5FD507EA8A743A9EB966DD0E4E
Signature
ecdsa-with-SHA384
Public key
EC 256 prime256v1

Subject alternative names (SAN)

DNS:dns.gda.pl, DNS:www.dns.gda.pl

SHA-256 fingerprint

E8:22:D8:C6:DA:AE:EF:02:2A:DC:B4:9E:7B:92:72:89:CD:8C:ED:87:35:16:69:EA:21:26:27:47:AD:70:D4:1C
Certificate extensions & PEM
basicConstraints
CA:FALSE
authorityKeyIdentifier
E9:99:06:8D:17:1F:AB:FB:96:1A:5A:C8:5B:5E:5D:5E:EC:DA:9C:8F
authorityInfoAccess
CA Issuers - URI:http://crt.harica.gr/HARICA-GEANT-TLS-E1.cer
subjectAltName
DNS:dns.gda.pl, DNS:www.dns.gda.pl
certificatePolicies
Policy: 2.23.140.1.2.2 Policy: 0.4.0.2042.1.7 Policy: 1.3.6.1.4.1.26513.1.1.1.2
extendedKeyUsage
TLS Web Client Authentication, TLS Web Server Authentication
crlDistributionPoints
Full Name: URI:http://crl.harica.gr/HARICA-GEANT-TLS-E1.crl
subjectKeyIdentifier
A6:9B:14:EC:D4:E6:61:86:A4:C7:BF:73:F1:55:BD:43:A8:56:B8:DE
keyUsage
Digital Signature
ct_precert_scts
Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 46:A2:39:67:C6:0D:B6:46:87:C6:6F:3D:F9:99:94:76: 93:A6:A6:11:20:84:57:D5:55:E7:E3:D0:A1:D9:B6:46 Timestamp : Jul 23 04:44:22.066 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:44:02:20:6B:59:1A:53:46:0E:7C:61:A8:6C:D8:7D: 12:E8:5E:BD:EE:25:CE:3A:B7:D6:1F:4D:34:DE:AF:03: A6:A7:19:AA:02:20:7D:67:62:01:C1:AD:58:FE:06:AA: 49:9A:D4:06:14:F3:8D:07:CF:4E:61:C5:E5:AB:0A:7D: 6D:2A:CD:04:F0:E5 Signed Certificate Timestamp: Version : v1 (0x0) Log ID : D6:D5:8D:A9:D0:17:53:F3:6A:4A:A0:C7:57:49:02:AF: EB:C7:DC:2C:D3:8C:D9:F7:64:C8:0C:89:19:1E:9F:02 Timestamp : Jul 23 04:44:22.056 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:45:02:20:3E:66:5E:49:3C:D7:0C:A3:8A:D4:23:7F: F3:A6:41:6C:06:06:8F:C1:84:E7:49:73:44:CC:B7:0B: 35:86:58:C1:02:21:00:E1:22:BD:2A:50:A0:77:C7:FE: 42:CF:F8:72:10:8C:C1:27:B9:24:76:11:D0:01:A1:C7: 94:D1:85:B1:81:AE:4B 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 : Jul 23 04:44:22.014 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:45:02:21:00:99:61:F8:1C:50:DE:60:E0:DB:16:7B: BB:88:6C:85:EA:04:E9:4A:BA:A0:D0:F9:B3:A7:F5:6F: 39:18:DB:10:04:02:20:52:F0:26:14:62:F5:3B:4F:49: AE:67:44:26:A6:8C:33:E9:CD:37:72:11:85:CE:D6:A6: F1:6A:D2:07:06:AA:57
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_128_GCM_SHA256 · Checked 2026-09-26T04:42:55+00:00

Server-presented chain · 2 additional certificates

Chain certificate 1

Subject
C=GR O=Hellenic Academic and Research Institutions CA CN=GEANT TLS ECC 1
Issuer
C=GR O=Hellenic Academic and Research Institutions CA CN=HARICA TLS ECC Root CA 2021
Valid from
2025-01-03T11:14:21+00:00
Expires
2039-12-31T11:14:20+00:00
Days remaining
4844
Serial (hex)
42FDDCE1261607E1A5E6935A400161DD
Signature
ecdsa-with-SHA384
Public key
EC 384 secp384r1

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

6C:DF:0B:A1:71:1E:85:6D:22:8B:A0:0C:A0:4C:5C:1C:3D:79:94:4C:03:7B:71:3B:15:5A:4E:E4:B4:7E:C5:3C
Certificate extensions & PEM
basicConstraints
CA:TRUE, pathlen:0
authorityKeyIdentifier
C9:1B:53:81:12:FE:04:D5:16:D1:AA:BC:9A:6F:B7:A0:95:19:6E:CA
authorityInfoAccess
CA Issuers - URI:http://crt.harica.gr/HARICA-TLS-Root-2021-ECC.cer
certificatePolicies
Policy: X509v3 Any Policy
extendedKeyUsage
TLS Web Client Authentication, TLS Web Server Authentication
crlDistributionPoints
Full Name: URI:http://crl.harica.gr/HARICA-TLS-Root-2021-ECC.crl
subjectKeyIdentifier
E9:99:06:8D:17:1F:AB:FB:96:1A:5A:C8:5B:5E:5D:5E:EC:DA:9C:8F
keyUsage
Digital Signature, Certificate Sign, CRL Sign
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Chain certificate 2

Subject
C=GR O=Hellenic Academic and Research Institutions CA CN=HARICA TLS ECC Root CA 2021
Issuer
C=GR L=Athens O=Hellenic Academic and Research Institutions Cert. Authority CN=Hellenic Academic and Research Institutions ECC RootCA 2015
Valid from
2021-09-02T07:44:37+00:00
Expires
2029-08-31T07:44:36+00:00
Days remaining
1070
Serial (hex)
716027C8857A73542DEF516C1C2EEB0F
Signature
ecdsa-with-SHA384
Public key
EC 384 secp384r1

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

50:E2:7F:90:EB:6A:F4:95:B0:E6:EE:B6:55:CC:89:44:4C:27:D3:C9:5B:68:23:FA:02:AB:DC:95:F1:63:6A:E1
Certificate extensions & PEM
basicConstraints
CA:TRUE
authorityKeyIdentifier
B4:22:0B:82:99:24:01:0E:9C:BB:E4:0E:FD:BF:FB:97:20:93:99:2A
authorityInfoAccess
CA Issuers - URI:http://repo.harica.gr/certs/HaricaECCRootCA2015.crt
certificatePolicies
Policy: X509v3 Any Policy
extendedKeyUsage
TLS Web Client Authentication, TLS Web Server Authentication
crlDistributionPoints
Full Name: URI:http://crl.harica.gr/HaricaECCRootCA2015.crl
subjectKeyIdentifier
C9:1B:53:81:12:FE:04:D5:16:D1:AA:BC:9A:6F:B7:A0:95:19:6E:CA
keyUsage
Digital Signature, Certificate Sign, CRL Sign
-----BEGIN CERTIFICATE-----
MIIDezCCAwGgAwIBAgIQcWAnyIV6c1Qt71FsHC7rDzAKBggqhkjOPQQDAzCBqjEL
MAkGA1UEBhMCR1IxDzANBgNVBAcTBkF0aGVuczFEMEIGA1UEChM7SGVsbGVuaWMg
QWNhZGVtaWMgYW5kIFJlc2VhcmNoIEluc3RpdHV0aW9ucyBDZXJ0LiBBdXRob3Jp
dHkxRDBCBgNVBAMTO0hlbGxlbmljIEFjYWRlbWljIGFuZCBSZXNlYXJjaCBJbnN0
aXR1dGlvbnMgRUNDIFJvb3RDQSAyMDE1MB4XDTIxMDkwMjA3NDQzN1oXDTI5MDgz
MTA3NDQzNlowbDELMAkGA1UEBhMCR1IxNzA1BgNVBAoMLkhlbGxlbmljIEFjYWRl
bWljIGFuZCBSZXNlYXJjaCBJbnN0aXR1dGlvbnMgQ0ExJDAiBgNVBAMMG0hBUklD
QSBUTFMgRUNDIFJvb3QgQ0EgMjAyMTB2MBAGByqGSM49AgEGBSuBBAAiA2IABDgI
/rGgltJ6rK9JOtDA4MM7KKrxcm1lAEeIhPyaJmuqS7psBAqIXhfyVYf8MLA04jRY
VxqEU+kw2anylnTDUR9YSTHMmE5gEYd103KUkE+bECUqqHgtvpBBWJAVcqeht6OC
AScwggEjMA8GA1UdEwEB/wQFMAMBAf8wHwYDVR0jBBgwFoAUtCILgpkkAQ6cu+QO
/b/7lyCTmSowTwYIKwYBBQUHAQEEQzBBMD8GCCsGAQUFBzAChjNodHRwOi8vcmVw
by5oYXJpY2EuZ3IvY2VydHMvSGFyaWNhRUNDUm9vdENBMjAxNS5jcnQwEQYDVR0g
BAowCDAGBgRVHSAAMB0GA1UdJQQWMBQGCCsGAQUFBwMCBggrBgEFBQcDATA9BgNV
HR8ENjA0MDKgMKAuhixodHRwOi8vY3JsLmhhcmljYS5nci9IYXJpY2FFQ0NSb290
Q0EyMDE1LmNybDAdBgNVHQ4EFgQUyRtTgRL+BNUW0aq8mm+3oJUZbsowDgYDVR0P
AQH/BAQDAgGGMAoGCCqGSM49BAMDA2gAMGUCMQCPc45gQV6pCkMR4px3k+YnF0Mo
DpXQ0+0lWz7fnplqgHn+qHmoKrE5Y/bcWucG6QQCMB/DIYjUTGAl5j07G7ZIuK3Q
ehx68VPXTwvJ9tLbh9A9SkiBmJGpiHL7Rzfxa5CptQ==
-----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 →