Detailed Explanation of Domain Name Hierarchy

Understanding the hierarchical structure of domain names is key to managing them. This article breaks down each component of a domain name in the simplest possible way.

1. Components of Domain Name Hierarchy

A domain name is divided into three levels from right to left:

1. Top-Level Domain (TLD): The rightmost part
2. Second-Level Domain: The core part in the middle
3. Third-Level Domain (Subdomain): The leftmost part

Example: help.racent.com

• .com → Top-Level Domain
• racent → Second-Level Domain
• help → Third-Level Domain (Subdomain)

2. Detailed Explanation of Each Domain Level

1. Top-Level Domain (TLD)

• Definition: The final part of a domain name
• Purpose: Identifies the type or region of the domain name
• Common types:
  • .com (commercial)
  • .org (organization)
  • .cn (China)
  • .app (application)

2. Second-Level Domain

• Definition: The core part before the top-level domain
• Key characteristics:
  • The part that users actually register
  • Represents a brand or organizational identifier
  • The registrant has full administrative permissions
• Examples:
  • "racent" in racent.com
  • "google" in google.com

✅ Important Note: When you register a domain name, you obtain ownership of the combination of second-level domain + top-level domain

3. Third-level Domain (Subdomain)

• Definition: The part preceding the second-level domain
• Key Features:
  • Can be created freely by the domain owner
  • No additional registration fee required
  • Unlimited number allowed
• Common Uses:
  • www.racent.com (main website)
  • shop.racent.com (e-commerce platform)
  • mail.racent.com (corporate email)

III. Ownership and Fees

Level	Example	Ownership	Fee
Top-level domain	.com	Managed by ICANN	Not sold separately
Second-level domain	racent.com	Fully owned by the user	Paid annually
Third-level domain	blog.racent.com	Independently created by the user	Permanently free

IV. Why Do You Need Subdomains?

1. Business Segmentation: Operate different services independently
2. Regional Deployment: Manage sites by geographic region
3. Test Environment: Dedicated space for development and testing
4. Simplified Access: Direct access to specific services