🔒 SSL Certificate Checker

🔧 Manual Checking Methods:

1. Using OpenSSL (Command Line):

# Check certificate
openssl s_client -connect example.com:443 -servername example.com

# Show expiry date
echo | openssl s_client -connect example.com:443 -servername example.com 2>/dev/null | openssl x509 -noout -dates

# Show full chain
openssl s_client -connect example.com:443 -servername example.com -showcerts

2. Using Browser DevTools:

• Visit the HTTPS site in Chrome/Firefox
• Click the padlock icon in address bar
• Click "Certificate" or "Connection is secure"
• View expiry date, issuer, and chain

3. Using curl:

curl -vI https://example.com 2>&1 | grep -A 10 "SSL connection"

📋 What to Check:

⚙️ Automated Monitoring Tools:

• certbot renew --dry-run - Test Let's Encrypt renewal
• SSL Monitoring Services: Uptime Robot, Pingdom, StatusCake
• nagios-check-ssl-cert - Nagios plugin for cert monitoring
• ssl-cert-check - Shell script for expiry alerts