NGINX: NGINX config for Level 4 proxy

stream {
    
    upstream allbackend {
        server 127.0.0.1:2222;
        server 127.0.0.1:3333;
        server 127.0.0.1:4444;
        server 127.0.0.1:5555;
    }
    

    server {
          listen 80;
          proxy_pass allbackend;
 
     }

}

events { } 

This configuration is for Nginx stream module, which is used for handling TCP or UDP traffic (rather than HTTP). It is commonly used for load balancing and proxying for non-HTTP protocols like database connections, email servers, or any other type of stream-based protocol.

Breakdown of the Configuration:

1. Stream Block

stream {
    ...
}

• The stream block is used to configure the stream module in Nginx, which handles TCP and UDP connections. This is different from the http block used for web traffic.

---

2. Upstream Definition (allbackend)

upstream allbackend {
    server 127.0.0.1:2222;
    server 127.0.0.1:3333;
    server 127.0.0.1:4444;
    server 127.0.0.1:5555;
}

• The upstream block defines a group of backend servers. In this case, the backend servers are all running on the same machine (127.0.0.1 or localhost), but they are listening on different ports (2222, 3333, 4444, 5555).
• This block allows Nginx to distribute incoming stream (TCP/UDP) traffic among these backend servers for load balancing.

---

3. Server Block (Stream Proxying)

server {
    listen 80;
    proxy_pass allbackend;
}

• This server block listens on port 80 for incoming TCP connections.
• The proxy_pass allbackend; directive tells Nginx to forward these incoming connections to the backend servers defined in the allbackend upstream block.
  • Nginx will load balance between the four backend servers (127.0.0.1:2222, 127.0.0.1:3333, 127.0.0.1:4444, and 127.0.0.1:5555) for any incoming TCP traffic on port 80.
• This configuration is useful for scenarios where you want to distribute TCP traffic (such as database, game server, or custom protocol traffic) to multiple backend servers.

---

4. Events Block

events { }

• The events block is empty but required for Nginx to function. It manages worker processes and connection handling, similar to the HTTP block, but it’s not used in the stream module itself.

---

Summary of How it Works:

• Upstream Block: Defines four backend servers (running on different ports) where the stream traffic will be forwarded.
• Server Block: Listens for TCP connections on port 80 and forwards them to the backend servers defined in the allbackend upstream block, distributing the traffic across those servers.
• This is typically used for load balancing and proxying non-HTTP traffic, such as TCP-based protocols (e.g., MySQL, PostgreSQL, or custom TCP services).

Use Case Example:

• Suppose you have a service running on multiple instances (e.g., a game server, or a database), and you want Nginx to act as a load balancer. It will listen for incoming TCP connections on port 80 and forward those connections to one of the four backend servers (127.0.0.1:2222, 127.0.0.1:3333, etc.) based on the load balancing algorithm.

This configuration is quite simple but effective for handling TCP stream traffic!

Back to Parent Page