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Here’s a blog-ready, copyright-free article explaining Zone vs. Domain vs. Subdomain in DNS.
Zone vs. Domain vs. Subdomain in DNS
When learning DNS, people often get confused between the terms zone, domain, and subdomain. They sound similar, but each has a specific meaning in the Domain Name System. Let’s break them down in simple terms.
1. Domain
A domain is simply a name in the DNS hierarchy. It represents a space where resources (like websites, mail servers, or services) are identified.
- Examples:
example.com(a second-level domain under.com)google.ca(a second-level domain under.ca)org(a top-level domain)
Domains are names, not servers or files. They’re like addresses in a global naming system.
2. Subdomain
A subdomain is any domain that exists below another domain in the DNS hierarchy.
- Example:
shop.example.comis a subdomain ofexample.com.us.shop.example.comis a subdomain ofshop.example.com.
Every part of a domain name (except the root .) can be broken into levels:
- Top-level domain (TLD):
.com - Second-level domain:
example.com - Third-level (subdomain):
shop.example.com - Fourth-level (sub-subdomain):
us.shop.example.com
👉 In short: All subdomains are domains, but not all domains are subdomains.
3. Zone
A zone is about administrative control, not just names.
- A zone is the portion of the DNS namespace that a particular DNS server is responsible for.
- It contains the records for that domain and possibly some subdomains.
Example:
- The
example.comzone may contain records for:www.example.commail.example.comftp.example.com
- But if
shop.example.comis delegated to another DNS server, thenshop.example.combecomes its own zone with its own administrator and authoritative server.
👉 So, a zone is a container of DNS records managed together, while a domain is just a name.
4. Putting It Together
- Domain: A name in DNS (
example.com). - Subdomain: A child domain under another (
shop.example.com). - Zone: The administrative boundary of authority that holds DNS records for a domain (and sometimes its subdomains).
✅ Summary for readers:
- A domain is a name.
- A subdomain is a domain under another domain.
- A zone is the portion of DNS managed by a specific server, which may or may not include all subdomains.
