Exploring Web Server Information via Command Line with wget and curl

In the vast landscape of the internet, understanding the technology powering the websites we interact with can be both enlightening and practical. Whether you're a curious user, a web developer, or a security enthusiast, knowing how to extract server information from a website can provide valuable insights. In this blog post, we'll explore two command-line tools, wget and curl, and how they can be used to fetch web server details effortlessly.

Unveiling the Web Server: An Introduction

Web servers play a fundamental role in delivering web content to users' browsers. They handle incoming HTTP requests, process them, and send back the appropriate responses. Knowing the type and version of the web server software can offer clues about the website's infrastructure, security practices, and optimization techniques.

Introducing wget and curl

wget: Often hailed as the "non-interactive network downloader," wget is a versatile command-line tool for downloading files from the web. Beyond fetching files, wget can also be used to inspect server responses, thanks to its --server-response flag. Combined with --spider, which simulates a web spider, wget can send HTTP requests without actually downloading the content.

curl: Another powerful tool in the command-line arsenal is curl, short for "Client URL." Like wget, curl can fetch data from URLs, but it also excels in displaying HTTP headers with its -I flag. This feature allows users to retrieve only the headers of a URL, including crucial information like the server type and version.

Fetching Server Information with wget

Let's dive into the world of wget. Suppose we want to examine the server information for a website, say, "https://blog.lalatendu.info". We can use the following command:

wget --server-response --spider https://blog.lalatendu.info 2>&1 | grep -i "Server:"

Here's what each part of the command does:

• --server-response: Instructs wget to display server responses.

• --spider: Tells wget to behave like a web spider, crawling without downloading.

• 2>&1: Redirects stderr (standard error) to stdout (standard output).

• grep -i "Server:": Filters the output to display only lines containing "Server:", ignoring case.

Extracting Server Details with curl

Now, let's shift our focus to curl. Using the same website, we can extract the server information with the following command:

curl -I https://blog.lalatendu.info | grep -i '^server:'

In this command:

• -I: Retrieves only the headers of the URL.

• grep -i '^server:': Searches for lines starting with "Server:", case-insensitively.

Additional Methods for Gathering Server Information

While wget and curl offer convenient ways to retrieve web server details from the command line, there are other approaches you can explore:

1. Online Tools: Utilize online services like WhatIsMyServer, SecurityTrails, and BuiltWith to obtain web server information by inputting a website URL.

2. Browser Developer Tools: Access the Network tab in your browser's developer tools to inspect network requests and responses, including server information.

3. HTTP Headers Browser Extensions: Install browser extensions that enable you to view HTTP headers directly from your browser, making it easy to inspect server information without leaving the browser window.

4. Security Vulnerability Scanners: Employ security vulnerability scanners such as Nikto, Nessus, and OpenVAS, which can automatically detect and report server information as part of their scanning process.

5. DNS Lookup Tools: Perform DNS lookups on domains to identify hosting providers or CDNs being used, providing insights into the underlying web server technology.

Conclusion: Empowering Exploration through CLI

With wget and curl at our disposal, unraveling web server details becomes a straightforward task. Whether analyzing website infrastructures, troubleshooting issues, or satisfying curiosity, these command-line tools offer a glimpse into the digital backbone of the internet. By mastering these commands, embark on a journey of discovery, one URL at a time.

In conclusion, wget and curl exemplify the power of command-line interfaces in accessing and understanding web server information. Armed with these tools, users can unravel the mysteries of the internet's underlying technologies, enriching their knowledge and enhancing their digital experiences.