Server_name vs HTTP_host: A Comprehensive Guide for Dev

Hello Dev! Have you ever been confused about the difference between the server_name and http_host variables in web development? Look no further, because in this article, we will explore the differences between these two variables and how they affect your website’s performance and security.

Introduction

When building websites, developers often encounter the server_name and http_host variables. While they might seem similar, they perform different functions and understanding their differences is crucial to building a high-performing website. In this section, we will introduce these variables and provide an overview of what to expect in this article.

What is server_name?

The server_name variable identifies the server that is processing the request. In other words, it tells the web server which site to display. This variable is set in the server’s configuration file and is used to determine which virtual host or server block to use. Server blocks are a way to host multiple websites on the same server with different configurations.

What is http_host?

The http_host variable, on the other hand, identifies the hostname that is used in the HTTP request. This variable is sent by the client’s web browser and is used by the web server to determine which website to serve. It is important to note that this variable can be manipulated by the client and, therefore, should not be used for security-related checks.

Server_name vs http_host

Now that we have introduced the server_name and http_host variables, let’s compare them side-by-side.

Variable	Function	Scope
server_name	Identifies the server that is processing the request	Defined in the server’s configuration file
http_host	Identifies the hostname that is used in the HTTP request	Sent by the client’s web browser

Differences in Function

The main difference between server_name and http_host is their function. While both variables identify a hostname, server_name identifies the server while http_host identifies the hostname used in the HTTP request.

Server_name is used to determine which virtual host or server block to use. This allows developers to host multiple websites on the same server with different configurations. Http_host, on the other hand, is used by the web server to determine which website to serve.

Differences in Scope

Another important difference between server_name and http_host is their scope. Server_name is defined in the server’s configuration file and is applicable to all requests processed by the server. Http_host, on the other hand, is sent by the client’s web browser and is specific to each HTTP request.

This means that server_name is set globally and applies to all requests, while http_host can be different for each request. Developers must take this into account when designing their website’s architecture and security measures.

Use Cases

Now that we have compared server_name and http_host, let’s explore their individual use cases and how they can affect your website’s performance and security.

Server_name Use Cases

Server_name is used primarily for virtual hosting, where multiple websites are hosted on the same server with different configurations. Virtual hosting allows developers to use a single physical server to host multiple websites, reducing hardware and maintenance costs.

Server_name can also be used to set default values for variables that are used across all server blocks. For example, developers can set the default error pages, timeouts, and cache settings for all websites hosted on the server.

HTTP_host Use Cases

Http_host is primarily used to serve the correct website to the user. This variable is sent by the client’s web browser and is used by the web server to determine which website to serve.

Http_host can also be used for load balancing and caching. By using http_host, the web server can serve the correct website to the user and cache the website’s content to reduce server load and improve performance.

FAQ

What happens if the server_name and http_host variables are different?

If the server_name and http_host variables are different, the web server may return a 404 error, serve the wrong website, or be vulnerable to security attacks. It is important to ensure that these variables are set correctly and match each other.

Can the http_host variable be manipulated by the client?

Yes, the http_host variable can be manipulated by the client’s web browser. Therefore, it should not be used for security-related checks, such as authentication or authorization. Developers should use server-side validation and authentication methods for secure web development.

What are some best practices for using server_name and http_host?

Some best practices for using server_name and http_host include:

• Setting server_name correctly in the server’s configuration file
• Verifying that server_name and http_host match each other
• Using http_host for website-specific checks, such as load balancing and caching
• Using server-side validation and authentication methods for security-related checks

Conclusion

Server_name and http_host are important variables in web development that have different functions and scopes. Understanding the differences between these variables is crucial to building a high-performing website that is secure and reliable. By following best practices and using these variables correctly, developers can ensure that their website is optimized for performance and security.