In web hosting, what is name based hosting and how does it allow multiple websites to share a single IP address?

Introduction / Context:
Modern shared hosting providers often run hundreds or even thousands of websites on a single physical server and IP address. Name based hosting is the technique that makes this possible. It is the opposite of IP based hosting and relies on information in the HTTP request to route traffic correctly. This question checks whether you understand that name based hosting uses the Host header so that multiple domains can share the same IP address.

Given Data / Assumptions:

• Many different domain names can resolve to the same IP address in DNS.
• The HTTP protocol includes a Host header that specifies which domain the client wants.
• A single web server instance listens on the shared IP address.
• The question asks what name based hosting is and how it works.

Concept / Approach:
In name based hosting, DNS for many domains points to one IP address. When a browser sends an HTTP or HTTPS request, it includes the Host header, which contains the domain name requested, such as example.com or example.org. The web server, such as Apache or Nginx, is configured with virtual hosts that match these domain names. Based on the Host header, the server chooses the correct virtual host configuration and serves the appropriate website files. This approach allows efficient use of IP addresses, which is especially important with IPv4 scarcity, and is widely used for both HTTP and modern HTTPS sites with Server Name Indication support.

Step-by-Step Solution:
Step 1: Recall that in name based hosting many domains share one IP address instead of each site having a dedicated IP. Step 2: Remember that the browser includes the domain name in the Host header when making a request. Step 3: Understand that the web server reads this Host header and maps the request to the correct virtual host configuration. Step 4: Select the option that explicitly mentions using the HTTP Host header so multiple domains can share a single IP.

Verification / Alternative check:
You can verify by inspecting a typical shared hosting configuration. In Apache, for instance, multiple VirtualHost definitions use the same IP and port but different ServerName values. When a request arrives, Apache uses the Host header to choose the right block. Most low cost hosting plans use this pattern, which confirms that name based hosting is about sharing a single IP address among many domains using the Host header.

Why Other Options Are Wrong:
Option B describes IP based hosting, not name based hosting. Option C is incorrect because MAC addresses operate at the local network layer and are not used to identify websites on the internet. Option D reverses the concept of name based hosting and incorrectly states that only IP addresses are used. Option E is wrong because DNS stores mappings between names and IP addresses, not full web page content for hosting.

Common Pitfalls:
A common pitfall is to assume that each domain must have its own IP address. In reality, name based hosting is the default on most shared hosting platforms. Another mistake is to overlook the role of the Host header and focus only on DNS. While DNS maps names to IP addresses, the Host header is what allows a single server on that IP to distinguish between different websites. Understanding this separation of responsibilities is important for troubleshooting hosting and DNS issues.

Final Answer:
Name based hosting uses the HTTP Host header to distinguish multiple domain names on the same IP address so that one server can host many websites