Reverse Proxy

Reverse proxies enhance security, performance, and reliability by acting as an intermediary between clients and backend infrastructure.

Why it matters

• Protects backend servers from direct exposure to the Internet.
• Enables SSL/TLS termination, offloading encryption overhead from application servers.
• Provides caching to reduce backend load and improve response times.
• Facilitates zero-downtime deployments and blue-green releases.
• Essential for web application security and DDoS mitigation.

Key capabilities

• SSL termination: Decrypt HTTPS traffic at the proxy, simplifying certificate management.
• Caching: Store static content and API responses to reduce backend requests.
• Compression: Gzip or Brotli compress responses to reduce bandwidth.
• Request routing: Direct traffic to different backends based on URL path or headers.
• Load balancing: Distribute requests across multiple backend servers.
• Request/response modification: Add headers, rewrite URLs, or transform content.

Security benefits

• Origin hiding: Backend servers are not directly addressable from the Internet.
• Web Application Firewall (WAF): Inspect and filter malicious requests.
• Rate limiting: Prevent abuse and brute-force attacks at the edge.
• DDoS protection: Absorb attack traffic before it reaches backends.
• Security headers: Inject CSP, HSTS, X-Frame-Options, and other protective headers.

Forward proxy vs reverse proxy

• Forward proxy: Sits in front of clients, forwarding requests to the Internet (e.g., corporate proxy, VPN).
• Reverse proxy: Sits in front of servers, receiving requests from the Internet (e.g., Nginx, Cloudflare).

Common implementations

• Web servers: Nginx, Apache, Caddy.
• CDNs: Cloudflare, Fastly, Akamai, AWS CloudFront.
• Application delivery: HAProxy, Traefik, Envoy.
• Cloud services: AWS ALB, Azure Application Gateway.

Configuration best practices

• Enable HTTP Strict Transport Security (HSTS) to enforce HTTPS.
• Set appropriate timeouts to prevent slow-loris attacks.
• Configure connection pooling to backend servers for efficiency.
• Implement health checks to route traffic away from failing backends.
• Log all requests for security analysis and troubleshooting.