Proxy

proxy_pass <scheme>://<host>[:port][/<URI>];

Ref: Nginx reverse proxy

If proxy_pass with URI

The part of URI matching the location is replaced by proxy_pass URI

location /path/ {
    proxy_pass http://www.example.com/app/;
}

• Request /path/page.html will be proxy to http://www.example.com/app/page.html
• Prefix /path/ will be replaced by /app/

If proxy_pass without URI

The request URI is passed to the server same as client request

location /path/ {
    proxy_pass http://www.example.com;
}

• Request /path/page.html will be proxy to http://www.example.com/path/page.html

Header

X-Forwarded-For

location / {
    # Set "Host" header to the $host in request
    proxy_set_header Host $host;

    # Set "X-Real-IP" header to client IP address
    proxy_set_header X-Real-IP $remote_addr;

    # Add client IP address to "X-Forwarded-For" header
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    
    proxy_pass http://localhost:8000;
}

Error

an upstream response is buffered to a temporary file /var/cache/nginx/proxy_temp/XXXXXX while reading upstream

Ref: K48373902

• Method 1

  Increase both parameters by factor of two until warning stop appearing

location / {
    proxy_buffers 16 16k;
    proxy_buffer_size 16k;

    proxy_pass http://localhost:8000;
}

• Method 2

  Disable buffering

location / {
    proxy_buffering off;

    proxy_pass http://localhost:8000;
}

server {
    listen 80;
    server_name www.example.com;

    location / {
        proxy_pass http://backends;
    }
}

SSL/TLS offloading

Ref: SSL/TLS Offloading, Encryption, and Certificates with NGINX and NGINX Plus

server {
    listen 443 ssl;
    server_name www.example.com;

    # The certificate file
    # Support chained certificate
    ssl_certificate www.example.com.crt;

    # The private key file
    ssl_certificate_key www.example.com.key;

    location / {
        proxy_pass http://10.0.0.1;
    }
}

WebSocket

WebSocket Proxy

Load balancing

Load balancing

Real (Client) IP address

Set $remote_addr and $remote_port using header

# set_real_ip_from  <proxy server IP address>[/<CIDR>];
# Trusted address
set_real_ip_from  10.0.0.1;

# by default, Nginx use X-Real-IP header to set $remote_addr

# Use X-Forwarded-For header to set $remote_addr
real_ip_header    X-Forwarded-For;
real_ip_recursive on;

# Use X-Real-IP header to set $remote_addr
real_ip_header    X-Real-IP;

Ref: ngx_http_realip_module

502 Bad Gateway

Ref: Ensuring Application Availability with F5 DNS Load Balancer Cloud Service and NGINX Plus

If Nginx cannot get response from backend server, Nginx will return 502 Bad Gateway