How to Check the Certificate Type?

Check if a certificate is self-signed

xxxxxxxxxx

openssl x509 -in cert.pem -text -noout

Look for: If the Issuer and Subject fields are the same, the certificate is self-signed.

Check if it’s CA-signed

xxxxxxxxxx

openssl x509 -in cert.pem -text -noout | grep Issuer

Look for: If the Issuer field contains a well-known CA (e.g., DigiCert, Let's Encrypt), it's CA-signed.

Check Certificate Chain (Intermediate CA)

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openssl s_client -connect server:port -showcerts

Look for: Multiple certificates being displayed. The Intermediate certificates appear before the root CA in the chain.