eTLD

An eTLD, or Effective Top-Level Domain, is a domain name that is used to identify a website, and which contains a TLD (Top-Level Domain) that has been delegated by ICANN (Internet Corporation for Assigned Names and Numbers). It is also known as a Public Suffix.

An eTLD is the part of the domain name that comes after the last dot, and which defines the domain’s root zone. For example, in the domain name “www.example.com”, “com” is the TLD, and “example.com” is the eTLD. The eTLD concept is important because it helps to identify the owner of the domain and the purpose of the website.

Purpose and Usage

The purpose of the eTLD is to provide a way to differentiate between different types of domain names, and to help identify the owner of the domain. This is important for several reasons:

• Security: Some organizations use subdomains to host different services or applications. For example, a bank might use “www.bank.com” for its public website, and “secure.bank.com” for its online banking service. By identifying the eTLD, browsers and other software can determine which subdomains are related and which are not. This helps prevent phishing attacks and other security threats.

• Privacy: Some websites use multiple subdomains to track user behavior or to serve personalized content. By identifying the eTLD, users can see which domains are related and can adjust their privacy settings accordingly.

• Consistency: By using the same eTLD for all subdomains, organizations can maintain a consistent brand identity and make it easier for users to remember their domain name.

Examples

Here are some examples of eTLDs and their corresponding TLDs:

• com: This is one of the most common eTLDs, and is used for commercial websites.

• org: This eTLD is used for non-profit organizations.

• edu: This eTLD is used for educational institutions.

• gov: This eTLD is used for government websites.

• co.uk: This eTLD is used for websites in the United Kingdom. In this case, “co” is the second-level domain, and “uk” is the TLD.

• com.au: This eTLD is used for websites in Australia. In this case, “com” is the second-level domain, and “au” is the TLD.

How eTLDs are Managed

eTLDs are managed by the Mozilla Public Suffix List, which is a list of all known eTLDs. The list is maintained by the Mozilla Foundation, and is used by web browsers and other software to determine which domains are related and which are not.

The Public Suffix List is constantly updated as new eTLDs are registered, and as old ones are retired. This helps to ensure that web browsers and other software can accurately identify eTLDs and prevent security threats.