Understanding the Difference between PHP HTTP_HOST and Server_Name

Hello Dev, are you familiar with the difference between PHP HTTP_HOST and server_name? Both are commonly used in web development, but their roles may not be clear to all. In this article, we will discuss the difference between these two server variables and how they can impact your website’s performance and security.

What is HTTP_HOST?

The HTTP_HOST variable is a PHP server variable that contains the domain name of the server that is currently running the PHP script. This variable is essential for separating requests to different web domains hosted on the same server.

The HTTP_HOST variable is usually set automatically by the webserver and contains the domain name of the current request, including the subdomain and port number (if specified). Here’s an example:

How is HTTP_HOST used?

The HTTP_HOST variable is often used in web development to dynamically generate URLs for web pages, API calls, and other backend operations. It’s also used to enforce domain-based security policies, like limiting access to certain pages or features based on the requesting domain.

For example, suppose you have a website that has both a public and a private section, and you want to restrict access to the private section to only users who are coming from your company’s network. In that case, you could use the HTTP_HOST variable to verify that the user’s request is coming from an authorized domain before granting access.

What is server_name?

The server_name variable is a server variable used by the Nginx web server to determine the domain name to use for processing a request.

The server_name value is usually set in the Nginx configuration file and can be used to define one or more domain names that the server should listen for. Here’s an example:

server {listen 80;server_name www.example.com;...}

In this example, Nginx will only accept requests to the domain www.example.com on port 80. If a request comes in with a different domain name or port number, it will be rejected.

How is server_name used?

The server_name variable is used by Nginx to match the requested domain name to a server block in the configuration file. Once the server block is identified, Nginx will use the configuration settings defined within that block to process the request.

For example, suppose you have a website that serves content in multiple languages based on the user’s browser settings. In that case, you could define separate server blocks for each language and use the server_name variable to route requests to the appropriate block.

What’s the Difference Between HTTP_HOST and server_name?

Now that we’ve covered the basics of each variable, let’s discuss the main differences between HTTP_HOST and server_name:

Which should you use?

The choice between HTTP_HOST and server_name depends entirely on the context in which they are being used. If you’re working with PHP scripts, you’ll likely use HTTP_HOST to generate dynamic URLs and enforce domain-based security rules. If you’re working with Nginx, you’ll use server_name to route requests to the correct server block and process them accordingly.

It’s worth noting that these variables are not mutually exclusive—some use cases may require the use of both variables in combination.

FAQs

What is a server variable?

A server variable is a special type of variable that is used by web servers to store information about the incoming request, the server environment, and other related data. These variables are commonly used in web development to create dynamic content, enforce security policies, and perform other backend operations.

Which server variables are available in PHP?

PHP supports a wide range of server variables, including HTTP_HOST, server_name, PHP_SELF, QUERY_STRING, and many others. These variables can be accessed within PHP scripts using the $_SERVER superglobal array.

Can HTTP_HOST be spoofed?

Like any server variable, HTTP_HOST can be spoofed by a malicious user trying to impersonate a legitimate domain. To mitigate this risk, it’s essential to use appropriate security measures like HTTPS encryption, domain validation, and other security best practices.

What happens if HTTP_HOST is not set?

If HTTP_HOST is not set, it can indicate a misconfiguration or an error in the webserver’s handling of the request. In some cases, the variable may be intentionally left blank in favor of using other server variables or configuration settings.

What happens if server_name is not set?

If server_name is not set, Nginx will not be able to match incoming requests to any server block in the configuration file, and the request will be rejected with an error message. It’s essential to ensure that the server_name value is correctly configured to avoid this issue.

That’s it for this article, Dev! We hope this has helped you understand the difference between HTTP_HOST and server_name and how they can impact your web development projects. If you have any questions or comments, feel free to let us know.