SSL Certificate Information
SSL/TLS certificate guide. Certificate types, providers, common issues, best practices. Secure your website with HTTPS.
Certificate Types
DV - Domain Validation: Basic, fast issuance
Use: Blogs, small sites | Time: Minutes | Cost: $0-50/year
OV - Organization Validation: Business identity verified
Use: Business sites | Time: 1-3 days | Cost: $50-200/year
EV - Extended Validation: Highest trust, green bar
Use: Banks, ecommerce | Time: 1-2 weeks | Cost: $150-500/year
Certificate Providers
Let's Encrypt: Free, automated, open (DV)
Cloudflare: Free SSL with CDN (DV/OV)
DigiCert: Enterprise, fast (OV/EV)
Sectigo: Budget-friendly (DV/OV)
GlobalSign: Enterprise solution (OV/EV)
Common SSL Issues & Fixes
Expired certificate: Renew certificate, auto-renew
Mixed content: Load all resources over HTTPS
Wrong hostname: Add domain to certificate
Untrusted root: Use trusted CA
Self-signed cert: Use public CA or trust locally
Weak cipher: Enable modern ciphers only
Best Practices
Use TLS 1.2+ minimum
Enable HSTS header
Auto-renew certificates
Use strong cipher suites
Implement OCSP stapling
Monitor expiration dates
Use wildcard for subdomains
Redirect HTTP to HTTPS
SSL Check Commands
openssl s_client -connect example.com:443
curl -vI https://example.com
nmap --script ssl-cert example.com
curl -vI https://example.com
nmap --script ssl-cert example.com
Browser Warnings
Chrome: Not secure in address bar. Firefox: Warning icon. Safari: Gray lock. Users avoid sites with warnings. SSL required for: AdSense, payment processing, app stores, SEO ranking. Google prioritizes HTTPS sites.