Learning Objectives
- Define a uniform resource locator as a text-based address for a web resource.
- Identify the protocol, domain name and web page or file name in a URL.
- Explain how each main URL component contributes to locating a resource.
- Interpret unfamiliar URLs accurately without relying on the visual appearance of a page.
Key Terms
- Uniform resource locator
- A text-based address used to identify the location of a web page or other web resource.
- Protocol
- A set of rules for communication; in a URL it may specify HTTP or HTTPS.
- Domain name
- The human-readable name associated with an internet location.
- Path
- The part of a URL that identifies a folder, page or resource on the server.
- Web page or file name
- The name of the particular resource requested, such as index.html or guide.pdf.
- Top-level domain
- The ending of a domain name, such as .com, .org or a country-code ending.
- Address bar
- The browser area in which a user can enter or view a URL.
Purpose Of A URL
A uniform resource locator, usually shortened to URL, gives a text-based address for a web page or another resource that can be requested through a web browser. It tells the browser what communication method to use and where the requested resource is located.
A URL is designed for people to read and enter more easily than a numeric IP address. The domain name within the URL can later be resolved to an IP address by the domain name server system.
Different pages on the same website need different addresses. The domain name identifies the website or server location, while the path and page or file name can identify the particular resource within that website.
Main Components Of A URL
Consider the URL https://www.example.org/revision/chapter5.html. The protocol is https. The domain name is www.example.org. The path is /revision/ and the file name is chapter5.html.
The syllabus requires candidates to understand that a URL can contain the protocol, the domain name and the web page or file name. Not every displayed URL must visibly contain all possible parts. A server may provide a default page when no file name is shown, and a browser may hide or shorten some parts for display.
The protocol indicates the rules used for the request. HTTP transfers web resources, while HTTPS protects the communication using security mechanisms. The domain name gives a readable name for the destination. The remaining path identifies the exact resource required.
Reading Domain Names Carefully
A domain name is read as a sequence of labels separated by dots. Users should inspect the actual domain rather than trusting words placed elsewhere in the URL. Attackers may create misleading names that contain a familiar brand as a subdomain or as part of a longer, different domain.
For examination purposes, candidates should identify the requested component exactly. If asked for the domain name, do not include the protocol or the path. If asked for the web page or file name, give only the final resource name where one is present.
URLs And User Navigation
A user can type a URL into the address bar, select a bookmark containing a saved URL, or follow a hyperlink that stores a destination URL. In each case, the browser uses the address to begin locating and requesting the resource.
The visible text of a hyperlink does not have to match its destination. This is why checking the URL attached to a link is an important security precaution. The destination should be examined before sensitive information is entered.
Breaking Down A URL
| URL Part | Example | Purpose |
|---|---|---|
| Protocol | https | Specifies the communication rules used to request the resource |
| Domain name | www.example.org | Provides the human-readable name of the destination |
| Path | /revision/ | Identifies a location or folder within the website |
| File name | chapter5.html | Identifies the particular page or file requested |
Worked Examples
Identifying URL Components
Question: For https://learn.example.net/course/unit1.html, identify the protocol, domain name and file name.
- Read from the start up to the colon to identify the protocol.
- Read the host portion after // and before the next /.
- Read the final named resource after the last /.
Answer: Protocol: https. Domain name: learn.example.net. File name: unit1.html.
Spotting A Misleading Domain
Question: A message displays the link text “Bank Login” but the destination is https://bank.secure-check.example/login. Why should the user be cautious?
- Do not judge the destination from the displayed link text.
- Inspect the actual domain labels.
- Identify that the registered destination is associated with example rather than necessarily with the bank.
Answer: The visible words do not prove the destination is genuine. The user should verify the actual domain before opening the page or entering login details.
Examination Guidance
- Separate URL components precisely in your answer.
- Remember that a URL is text-based; an IP address is numeric or hexadecimal depending on its version.
- Use the exact URL shown in the question rather than assuming a familiar website structure.
- For security questions, explain that the destination URL should be checked before following a link.
Common Mistakes
- Including https:// when the question asks only for the domain name.
- Calling the whole URL a domain name.
- Assuming that words at the beginning of a long address always identify the true organisation.
- Confusing a URL with the page content displayed by the browser.
Knowledge Check
1. What does URL stand for?
2. What is the main purpose of a URL?
3. Name three components that a URL can contain.
4. In https://example.com/files/report.pdf, what is the file name?
5. Why is checking the destination URL of a hyperlink useful?
