How to setup HTTP Strict Transport Security With Lighttpd Web Server

HTTP Strict Transport Security (HSTS) is a security feature that allows a web server to tell a client's web browser to only communicate with the server using secure HTTPS connections. This can help protect against attacks such as man-in-the-middle attacks, where an attacker could intercept and modify the traffic between the client and the server.

To setup HSTS with the Lighttpd web server, you will need to do the following:

1. Enable HTTPS on your Lighttpd server. This involves obtaining a SSL/TLS certificate for your domain and configuring Lighttpd to use HTTPS. For more information about how to do this, you can refer to the Lighttpd documentation or use the man command to view the manual pages for Lighttpd.

2. Add the mod_setenv module to your Lighttpd configuration. The mod_setenv module allows you to set environment variables and add custom headers to the server's responses. To add the mod_setenv module, you will need to add the following line to your Lighttpd configuration file:

server.modules += ( "mod_setenv" )

3. Set the Strict-Transport-Security header using the setenv.add-response-header directive. You can use the setenv.add-response-header directive to set the Strict-Transport-Security header for all HTTPS responses sent by the server. Here's an example of how to set the header with a maximum age of one year:

$SERVER["socket"] == ":443" {
  setenv.add-response-header = ( "Strict-Transport-Security" => "max-age=31536000" )
}

This configuration will set the Strict-Transport-Security header for all HTTPS responses sent by the server. The max-age value indicates the number of seconds that the client should remember to only communicate with the server using HTTPS.

4. (Optional) Set the includeSubDomains and preload flags. You can use the includeSubDomains flag to apply HSTS to all subdomains of the main domain, and the preload flag to preload the HSTS policy in the client's web browser. Here's an example of how to set both flags:

$SERVER["socket"] == ":443" {
  setenv.add-response-header = ( "Strict-Transport-Security" => "max-age=31536000; includeSubDomains; preload" )
}

Once you have completed these steps, HSTS should be setup on your Lighttpd web server. You can verify that the Strict-Transport-Security header is being set correctly by using a tool like the HTTP Header Checker or by inspecting the headers in the client's web browser.