The Nginx Proxy, Cloudflare Full SSL, and Load Balancer Redirection Loop Conundrum: A Step-by-Step Guide to Resolution

Are you caught in the seemingly endless cycle of redirection loops when attempting to integrate Nginx proxy, Cloudflare Full SSL, and a load balancer? Fear not, dear reader, for we’re about to embark on a journey to tame this beast and emerge victorious!

Understanding the Redirection Loop Problem

Before we dive into the solutions, it’s essential to grasp the underlying issue. The redirection loop occurs when the following conditions are met:

• Nginx is configured as a reverse proxy.
• Cloudflare Full SSL is enabled, which includes SSL encryption and SSL termination.
• A load balancer is introduced to distribute incoming traffic.

In this scenario, the load balancer redirects incoming requests to the Nginx proxy, which, in turn, forwards the requests to the origin server. However, since Cloudflare Full SSL is enabled, the browser receives an HTTPS response from the origin server, causing the browser to send a new request to the load balancer, and so on, ad infinitum.

Step 1: Configure Nginx as a Reverse Proxy

First, let’s configure Nginx as a reverse proxy. Create a new file in the `/etc/nginx/conf.d/` directory (the exact path may vary depending on your system) and add the following configuration:

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://origin-server;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

Replace `example.com` with your domain name, and `http://origin-server` with the URL of your origin server.

Step 2: Enable Cloudflare Full SSL

Next, enable Cloudflare Full SSL by following these steps:

1. Log in to your Cloudflare account and select the domain for which you want to enable Full SSL.
2. Navigate to the “SSL/TLS” tab and click on “Edge Certificates.”
3. Click on the “Create Certificate” button and select “Full SSL” as the certificate type.
4. Follow the instructions to generate and upload the certificate to Cloudflare.

With Cloudflare Full SSL enabled, incoming requests will be encrypted and terminated at the Cloudflare edge.

Step 3: Configure the Load Balancer

Now, let’s configure the load balancer to distribute incoming traffic:

Assuming you’re using a popular load balancer like HAProxy, add the following configuration:

frontend http
    bind *:80

    default_backend backend

backend backend
    balance roundrobin
    mode http
    server server1 example.com:80 check
    server server2 example.com:80 check

Replace `server1` and `server2` with the IP addresses or hostnames of your backend servers.

Step 4: Break the Redirection Loop

To break the redirection loop, we need to configure Nginx to forward the protocol (HTTP or HTTPS) from the load balancer to the origin server. Add the following code to your Nginx configuration:

http {
    ...
    upstream origin-server {
        server example.com;
    }

    server {
        listen 80;
        server_name example.com;

        location / {
            proxy_pass $scheme://origin-server;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-Proto $scheme;
        }
    }
}

The `$scheme` variable in `proxy_pass` ensures that the protocol is forwarded to the origin server. The `X-Forwarded-Proto` header is also set to inform the origin server about the original protocol used by the client.

Step 5: Configure Cloudflare to Trust the Load Balancer’s IP

To ensure that Cloudflare trusts the load balancer’s IP address, follow these steps:

1. Log in to your Cloudflare account and select the domain for which you want to enable trust.
2. Navigate to the “Security” tab and click on “Edge Certificates.”
3. Click on the “Edit” button next to “Trusted IP Addresses.”
4. Add the IP address of your load balancer to the trusted list.

This step is crucial, as it allows Cloudflare to recognize the load balancer’s IP address and prevent it from being flagged as an unknown entity.

Conclusion

By following these steps, you should now have a functioning setup with Nginx proxy, Cloudflare Full SSL, and a load balancer, free from the redirection loop menace. Remember to test your configuration thoroughly to ensure that everything is working as expected.

Troubleshooting Tips

If you still encounter issues, consider the following troubleshooting tips:

• Verify that the load balancer’s IP address is added to the Cloudflare trusted IP list.
• Check the Nginx configuration for any syntax errors or misconfigurations.
• Ensure that the origin server is properly configured to handle HTTPS requests.
• Test the setup using tools like `curl` or `wget` to simulate client requests.

Problem	Solution
Redirection loop persists	Check the Nginx configuration and ensure that the `$scheme` variable is correctly set.
Cloudflare SSL handshake fails	Verify that the Cloudflare Full SSL certificate is properly installed and configured.
Load balancer IP address is blocked	Add the load balancer’s IP address to the Cloudflare trusted IP list.

By following this step-by-step guide, you should now be able to create a harmonious configuration with Nginx proxy, Cloudflare Full SSL, and a load balancer, free from the shackles of the redirection loop. Happy configuring!

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