SSL Certificate

SSL/TLS Certificate Verification Guide

An expired or misconfigured SSL certificate causes browsers to block access to your website. This tool performs a real-time HTTPS handshake with your server to pull the public certificate and verify its details.

Supported Inputs

• Hostname: e.g., thenetworktools.com (Do not include https://)

How to Interpret the Output

• Valid From / Valid To: The start and expiration dates of the certificate.
• Issuer: The Certificate Authority (CA) that issued the certificate (e.g., Let’s Encrypt, DigiCert).
• Subject Alternative Names (SANs): The list of domains and subdomains the certificate is valid for.

Realistic Example

If you query a site using Let’s Encrypt:

• Issuer will show Let's Encrypt Authority X3 or similar.
• Valid To will be within 90 days of issuance.
• The tool will confirm if the current date falls within the validity window.

Common Errors & Limitations

• Connection Refused: The tool cannot connect if the server blocks traffic on port 443 or is offline.
• Basic Verification: This tool validates the certificate dates and issuer. It does not perform deep vulnerability scanning (like testing for Heartbleed or grading the cipher suites).