IPSSL Certificate Checker
Verify that HTTPS is working for any domain and check SSL/TLS certificate configuration. Detects whether HTTPS is accessible, HTTP is being redirected, HSTS is configured, and the certificate is being accepted by browsers. Essential for web administrators and security audits.
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What Does an SSL Certificate Checker Verify?
An SSL/TLS certificate checker verifies that a website's HTTPS security certificate is valid, properly configured, and not expired. SSL certificates are the cryptographic foundation of secure web browsing — they authenticate the server's identity and establish an encrypted connection between your browser and the server, preventing eavesdropping, man-in-the-middle attacks, and data tampering.
An expired or misconfigured SSL certificate causes browser security warnings that drive users away — regular monitoring prevents unexpected downtime
Common SSL Certificate Issues
| Issue | Browser Error | How to Fix |
|---|---|---|
| Expired certificate | ERR_CERT_DATE_INVALID, NET::ERR_CERT_DATE_INVALID | Renew the certificate. Let's Encrypt certificates are free and expire every 90 days — automate renewal with certbot. |
| Certificate for wrong domain | ERR_CERT_COMMON_NAME_INVALID | Ensure the certificate's Common Name or SAN (Subject Alternative Name) matches the domain exactly, including www vs non-www. |
| Self-signed certificate | ERR_CERT_AUTHORITY_INVALID | Browsers don't trust self-signed certs for production. Get a certificate from a trusted CA: Let's Encrypt (free), DigiCert, Sectigo. |
| Incomplete certificate chain | ERR_CERT_AUTHORITY_INVALID | Include intermediate CA certificates in your server's certificate bundle. Most CA providers supply a "fullchain" file. |
| HTTP not redirecting to HTTPS | Mixed content warnings | Add 301 redirect from HTTP to HTTPS. Add HSTS header: Strict-Transport-Security: max-age=31536000 |
| Mixed content (HTTP resources on HTTPS page) | Shield icon / security warnings | Ensure all images, scripts, stylesheets load via HTTPS. Update any hardcoded http:// URLs in your HTML/CSS. |
Let's Encrypt — Free SSL Certificates
Let's Encrypt (operated by the non-profit Internet Security Research Group) provides free, automated, and open SSL/TLS certificates. Over 300 million websites use Let's Encrypt certificates. Key facts:
- Cost: Completely free — no payment required
- Validity: 90 days — must be renewed every 90 days (automation via certbot is strongly recommended)
- Automation: certbot on Linux automates renewal with a cron job or systemd timer
- Supported by: All major browsers, operating systems, and applications
- Wildcard support: *.yourdomain.com wildcards available via DNS-01 validation
- India hosting: Works on all Indian hosting providers including those using cPanel/WHM
Frequently Asked Questions
How do I get a free SSL certificate?
Use Let's Encrypt — it provides free SSL/TLS certificates trusted by all major browsers. On Linux servers, install certbot (sudo apt install certbot python3-certbot-nginx) and run certbot --nginx. It automatically configures Nginx and sets up auto-renewal. Certificates are valid for 90 days and auto-renew.
Why is my SSL certificate showing as invalid?
Common causes: (1) Certificate expired — Let's Encrypt certs expire every 90 days, automate renewal. (2) Wrong domain — certificate must match the exact domain including www. (3) Self-signed certificate — not trusted by browsers. (4) Incomplete certificate chain — missing intermediate CA. (5) DNS not pointing to certificate-served server.
What is HSTS?
HTTP Strict Transport Security (HSTS) is a security header that tells browsers to only connect via HTTPS for a specified time period. Prevents SSL stripping attacks. Add to your server: Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
What is the difference between SSL and TLS?
SSL (Secure Sockets Layer) is the older protocol — SSL 2.0, 3.0 are deprecated and insecure. TLS (Transport Layer Security) is the modern replacement — TLS 1.2 and 1.3 are current. Modern servers use TLS but the term 'SSL certificate' persists colloquially. Ensure your server has SSLv3 and TLS 1.0/1.1 disabled.
Is this SSL checker free?
Yes — completely free, no signup required. Tests HTTPS connectivity, browser-accepted certificate status, response time, and HSTS configuration for any domain instantly.