SSL Lookup

What this SSL lookup checks

An SSL/TLS certificate encrypts traffic between a browser and a server and verifies the identity of the server. This tool connects to the specified host and port, retrieves the presented certificate, and displays key details such as the issuing organization, common name, issue and expiration dates, and signature algorithm.

Why certificate details matter

Expired or misconfigured certificates cause browser warnings, erode user trust, and can interrupt access to your site. Checking the common name confirms that the certificate covers the domain you expect. Reviewing the issuer helps distinguish between a publicly trusted certificate authority and a self-signed certificate. The signature type indicates the cryptographic algorithm used and may reveal outdated configurations.

Practical scenarios

• Before and after renewals. Confirm that the new certificate is active and that the expiration date has been extended.
• Migration checks. Verify that a certificate covers all required domain variants after moving hosting or changing providers.
• Security audits. Identify weak signature algorithms or certificates issued by unexpected authorities.
• Troubleshooting browser errors. Determine whether a warning is caused by expiration, a name mismatch, or an untrusted issuer.

Limitations

The tool retrieves the certificate currently served on the specified host and port. It does not validate the full certificate chain, test protocol versions, or assess overall server security. A certificate that appears valid here may still be part of an incomplete chain that some clients reject. Different server configurations or CDNs may present different certificates depending on the connection. Use this lookup as a first diagnostic step, not as a complete security assessment.