SSL Certificate Checker
1. Enter Hostname
Load Sample
2. SSL Certificate Details
Status–
Issuer–
Subject–
Valid From–
Valid To / Expiry–
Days Remaining–
Protocol Version–
How to Use the SSL Checker
- Enter the website URL or hostname.
- Specify the port (default is 443).
- Click “Check SSL” to initiate the scan.
- Review the certificate issuer and validity dates.
- Check for proper chain of trust and potential vulnerabilities.
Technical Logic
The tool establishes a TLS handshake with the target server. It parses the X.509 certificate data returned by the server. It verifies the expiration date against the current UTC time. Finally, it checks the certificate chain against a store of trusted root authorities.
Key Features
- Real-time certificate extraction.
- Expiry date and days-remaining calculation.
- Issuer and Subject Alternative Name (SAN) display.
- Chain of trust verification.
Reference Table: Common SSL Ports
| Protocol | Standard Port | Secure Port |
|---|---|---|
| HTTP / HTTPS | 80 | 443 |
| SMTP | 25 / 587 | 465 |
| IMAP | 143 | 993 |
| POP3 | 110 | 995 |
FAQ
Why is my SSL certificate invalid?
Common reasons include an expired date, a mismatched domain name, or a missing intermediate certificate in the chain.
How often should I check my SSL?
Set up automated checks weekly, and manually verify immediately after renewing or installing a new certificate.