How to Disable ETag in NGINX

NGINX is a powerful and versatile open-source software that can be used for various purposes such as HTTP server, reverse proxy, load balancer, and more. It is known for its high performance, stability, and rich feature set.

In the context of web servers, ETag or entity tag is part of the HTTP protocol intended for web cache validation, conditional requests, and to allow more efficient updates and synchronization of cache information. However, there might be situations where you’d want to disable ETags, such as for performance tuning or to avoid potential security vulnerabilities.

In this article, we’ll guide you through the process of disabling ETag in the NGINX web server.

Backup Your Configuration

Before we begin, it’s important to backup your existing configuration. In case something goes wrong, you can easily revert to the original settings. Here is the command to backup your main NGINX configuration file:

sudo cp /etc/nginx/nginx.conf /etc/nginx/nginx.conf.bak 

Steps to Disable ETag in NGINX

The NGINX web server does not generate ETags by default for dynamic content. However, it does generate ETags for static files. To disable ETag for static files, you will need to set the “etag” directive to “off” in the configuration file. Here are the steps:

Open the NGINX main configuration file using any text editor of your choice. If you are using nano editor, use the following command:

sudo nano /etc/nginx/nginx.conf 

Locate the http block in the configuration file. Inside the http block, look for the server block. If you have multiple server blocks, you will need to update each one individually.

In the server block, you need to add the following line to disable ETag:

etag off;

It should look something like this:

server {
    listen 80 default_server;
    listen [::]:80 default_server;
    etag off;
    . . .

After you have made the changes, save and close the file.

To check if the configuration file syntax is correct, run the following command:

sudo nginx -t 

If the syntax is correct, you should see a message similar to:

nginx: configuration file /etc/nginx/nginx.conf test is successful

If the syntax check passes, reload the NGINX configuration for the changes to take effect:

sudo systemctl reload nginx 

That’s it! You have successfully disabled ETag in your NGINX web server.

Final Thoughts

Disabling ETag in NGINX can help increase performance, particularly in environments where a reverse proxy or CDN is used. However, keep in mind that ETags are useful for cache control and should be disabled only when necessary. It’s important to carefully consider the implications of disabling any feature of a web server and, as always, ensure that changes are tested thoroughly in a controlled environment before deploying them to production servers.

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