Real_IP And Conditional Logging Working For Bookworm But Not Buster

Apr 20, 2025 by ADMIN 68 views

**Real_IP and Conditional Logging Working for Bookworm but Not Buster**

Introduction

In this article, we will discuss the issue of Real_IP and conditional logging not working for Debian Buster but working for Debian Bookworm in a setup involving two Pi4B web servers running nginx, located behind a proxy server (RPS) also running nginx. We will explore the possible causes and solutions to this problem.

Background Information

I have two Pi4B web servers running nginx located behind a proxy server (RPS) also running nginx. Web server 1 (WS1) was built several years ago using the Debian Buster OS, while web server 2 (WS2) was recently set up using the Debian Bookworm OS.

The Issue

The issue at hand is that Real_IP and conditional logging are not working as expected on WS1 (Debian Buster), but they are working fine on WS2 (Debian Bookworm). This has caused some inconvenience and has led to a thorough investigation of the problem.

Real_IP and Conditional Logging Configuration

To understand the issue better, let's take a look at the Real_IP and conditional logging configuration on both WS1 and WS2.

WS1 (Debian Buster)

On WS1, the Real_IP and conditional logging configuration is as follows:

http {
    ...
    real_ip_header X-Forwarded-For;
    real_ip_recursive on;
    ...
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                     '$status $body_bytes_sent "$http_referer" '
                     '"$http_user_agent" "$http_x_forwarded_for"';
    ...
    access_log /var/log/nginx/access.log main;
    ...
}

WS2 (Debian Bookworm)

On WS2, the Real_IP and conditional logging configuration is as follows:

http {
    ...
    real_ip_header X-Forwarded-For;
    real_ip_recursive on;
    ...
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                     '$status $body_bytes_sent "$http_referer" '
                     '"$http_user_agent" "$http_x_forwarded_for"';
    ...
    access_log /var/log/nginx/access.log main;
    ...
}

Differences in Configuration

At first glance, the Real_IP and conditional logging configuration on both WS1 and WS2 appears to be identical. However, upon closer inspection, there are some subtle differences in the configuration.

WS1 (Debian Buster)

On WS1, the real_ip_recursive directive is set to on, which enables recursive IP address resolution. This means that if the X-Forwarded-For header contains multiple IP addresses, nginx will recursively resolve each IP address to determine the original client IP address.

WS2 (Debian Bookworm)

On WS2, the real_ip_recursive directive is also set to on, which enables recursive IP address resolution. However, there is an additional directive real_ip_header X-Forwarded-For; which is not present on WS1.

Possible Causes of the Issue

Based on the differences in configuration, there are several possible causes of the issue:

Missing Directive: The missingreal_ip_header X-Forwarded-For;` directive on WS1 might be causing the issue. This directive is required to specify the header that contains the client IP address.
Recursive IP Address Resolution: The real_ip_recursive directive on WS1 is set to on, which enables recursive IP address resolution. This might be causing the issue if the X-Forwarded-For header contains multiple IP addresses.
Nginx Version: The issue might be related to the version of nginx being used on WS1 and WS2. Debian Buster uses an older version of nginx, while Debian Bookworm uses a newer version.

Solutions to the Issue

To resolve the issue, we can try the following solutions:

Add Missing Directive: Add the real_ip_header X-Forwarded-For; directive to the configuration on WS1 to specify the header that contains the client IP address.
Disable Recursive IP Address Resolution: Disable the real_ip_recursive directive on WS1 to prevent recursive IP address resolution.
Upgrade Nginx Version: Upgrade the version of nginx on WS1 to match the version used on WS2.

Conclusion

In conclusion, the issue of Real_IP and conditional logging not working for Debian Buster but working for Debian Bookworm can be caused by several factors, including missing directives, recursive IP address resolution, and differences in nginx version. By understanding the possible causes and solutions to the issue, we can resolve the problem and ensure that Real_IP and conditional logging work as expected on both WS1 and WS2.

Additional Information

For further information on Real_IP and conditional logging, please refer to the official nginx documentation:

References

Debian Buster
Debian Bookworm
Nginx Documentation
Real_IP and Conditional Logging Working for Bookworm but Not Buster: Q&A ====================================================================

Introduction

In our previous article, we discussed the issue of Real_IP and conditional logging not working for Debian Buster but working for Debian Bookworm in a setup involving two Pi4B web servers running nginx, located behind a proxy server (RPS) also running nginx. We explored the possible causes and solutions to this problem. In this article, we will provide a Q&A section to address some of the common questions related to this issue.

Q: What is Real_IP and Conditional Logging?

A: Real_IP and conditional logging are two important features in nginx that allow you to log the original client IP address and perform conditional logging based on various conditions.

Q: Why is Real_IP and Conditional Logging not working for Debian Buster?

A: The issue of Real_IP and conditional logging not working for Debian Buster can be caused by several factors, including missing directives, recursive IP address resolution, and differences in nginx version.

Q: What is the difference between Debian Buster and Debian Bookworm?

A: Debian Buster and Debian Bookworm are two different versions of the Debian operating system. Debian Buster is an older version, while Debian Bookworm is a newer version. The main difference between the two versions is the version of nginx used.

Q: How can I resolve the issue of Real_IP and Conditional Logging not working for Debian Buster?

A: To resolve the issue, you can try the following solutions:

Add Missing Directive: Add the real_ip_header X-Forwarded-For; directive to the configuration on WS1 to specify the header that contains the client IP address.
Disable Recursive IP Address Resolution: Disable the real_ip_recursive directive on WS1 to prevent recursive IP address resolution.
Upgrade Nginx Version: Upgrade the version of nginx on WS1 to match the version used on WS2.

Q: What are the benefits of using Real_IP and Conditional Logging?

A: The benefits of using Real_IP and conditional logging include:

Improved Logging: Real_IP and conditional logging allow you to log the original client IP address and perform conditional logging based on various conditions.
Better Security: Real_IP and conditional logging can help improve security by allowing you to log and track suspicious activity.
Enhanced Performance: Real_IP and conditional logging can help improve performance by allowing you to optimize your nginx configuration based on real-time data.

Q: How can I troubleshoot the issue of Real_IP and Conditional Logging not working for Debian Buster?

A: To troubleshoot the issue, you can try the following steps:

Check the Configuration: Check the nginx configuration on WS1 to ensure that the real_ip_header and real_ip_recursive directives are correctly set.
Check the Logs: Check the nginx logs on WS1 to see if there are any errors or warnings related to Real_IP and conditional logging.
Test the Configuration: Test the nginx configuration on WS1 to ensure that Real_IP and conditional logging are working correctly.

Conclusion**

Additional Information

For further information on Real_IP and conditional logging, please refer to the official nginx documentation: