# Nginx Configuration Examples

## Reverse Proxy with SSL

```nginx
# /etc/nginx/sites-available/myapp
server {
    listen 80;
    server_name myapp.example.com;
    return 301 https://$server_name$request_uri;
}

server {
    listen 443 ssl http2;
    server_name myapp.example.com;
    
    # SSL Configuration
    ssl_certificate /etc/letsencrypt/live/myapp.example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/myapp.example.com/privkey.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;
    ssl_prefer_server_ciphers on;
    
    # Security Headers
    add_header X-Frame-Options DENY;
    add_header X-Content-Type-Options nosniff;
    add_header X-XSS-Protection "1; mode=block";
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
    
    # Logging
    access_log /var/log/nginx/myapp.access.log;
    error_log /var/log/nginx/myapp.error.log;
    
    # Proxy to backend
    location / {
        proxy_pass http://127.0.0.1:3000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_cache_bypass $http_upgrade;
        
        # Timeouts
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
    }
    
    # Static files
    location /static/ {
        alias /var/www/myapp/static/;
        expires 30d;
        add_header Cache-Control "public, immutable";
    }
    
    # Health check endpoint
    location /health {
        access_log off;
        return 200 "healthy\n";
        add_header Content-Type text/plain;
    }
}
```

## Load Balancing Configuration

```nginx
# /etc/nginx/conf.d/upstream.conf
upstream backend {
    least_conn;
    server 10.0.1.10:3000 weight=3 max_fails=3 fail_timeout=30s;
    server 10.0.1.11:3000 weight=3 max_fails=3 fail_timeout=30s;
    server 10.0.1.12:3000 weight=1 backup;
}

server {
    listen 80;
    server_name api.example.com;
    
    location / {
        proxy_pass http://backend;
        proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;
        proxy_next_upstream_tries 3;
        proxy_next_upstream_timeout 30s;
        
        # Standard proxy headers
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}
```

## Rate Limiting

```nginx
# /etc/nginx/nginx.conf (in http block)
http {
    # Rate limiting zones
    limit_req_zone $binary_remote_addr zone=api:10m rate=10r/s;
    limit_req_zone $binary_remote_addr zone=login:10m rate=1r/s;
    
    # Connection limiting
    limit_conn_zone $binary_remote_addr zone=conn_limit_per_ip:10m;
}

# In server block
server {
    location /api/ {
        limit_req zone=api burst=20 nodelay;
        limit_conn conn_limit_per_ip 10;
        proxy_pass http://backend;
    }
    
    location /auth/login {
        limit_req zone=login burst=5;
        proxy_pass http://backend;
    }
}
```