Reverse Proxy

A reverse proxy is a server that accepts requests from clients on behalf of one or more backend servers, forwards them, and returns the backend's response. Clients talk only to the proxy and never see the backends. Nginx, HAProxy, Apache and Caddy are common examples, and CDNs act as reverse proxies at large scale.

Why it matters

A reverse proxy can terminate TLS, route by hostname or path, cache responses, compress content and spread load. It is also where many outages surface: when the backend is down or slow, the proxy returns 502 Bad Gateway or 504 Gateway Timeout instead of your page.

Example

A minimal nginx configuration passing traffic to an app on port 3000:

location / {
    proxy_pass http://127.0.0.1:3000;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_read_timeout 60s;
}

The X-Forwarded-* headers pass the original client IP and scheme to the application, which otherwise sees only the proxy.

Common mistakes

• Not forwarding Host or X-Forwarded-Proto, causing wrong redirect URLs or redirect loops after HTTPS.
• Trusting X-Forwarded-For from any source. Only accept it from your own proxy.
• Leaving default timeouts that are shorter than your slowest legitimate request.
• Debugging only the backend when the error is produced by the proxy, or the reverse.

Related

• Load balancer
• CDN
• HTTP status code
• गाइड: Fix 502 Bad Gateway
• टूल: HTTP header checker

यह पेज सामान्य जानकारी है, जिसे हमारी संपादकीय टीम ने लिखा है और दस्तावेज़ीकरण बदलने पर अपडेट किया जाता है। सर्वर और प्रदाता अलग-अलग होते हैं, इसलिए बदलाव पहले सुरक्षित तरीके से जाँचें। देखें: संपादकीय नीति और अस्वीकरण.