Top-Level Domain (TLD)
A Top-Level Domain (TLD) is the rightmost segment of a domain name (after the last dot). TLDs are the highest level of the DNS hierarchy below the root.
TLD Classifications
Section titled “TLD Classifications”Generic TLD (gTLD)
Section titled “Generic TLD (gTLD)”Originally intended for specific use cases, most gTLDs are now open to everyone.
- Legacy:
.com(commercial),.net(network),.org(organization). - New gTLDs: Thousands of niche extensions like
.app,.blog,.guru. - Restricted: Domains like
.bankor.pharmacyrequire verification of eligibility. - Brand: Closed TLDs for corporations, e.g.,
.googleor.bmw.
Country Code TLD (ccTLD)
Section titled “Country Code TLD (ccTLD)”Reserved for countries and territories (two letters, based on ISO 3166).
- Examples:
.uk(United Kingdom),.de(Germany),.io(British Indian Ocean Territory). - Rules: Policies vary strictly by country. Some require local residency (e.g.,
.no,.ca), while others are marketed globally (e.g.,.tv,.ai).
Sponsored TLD (sTLD)
Section titled “Sponsored TLD (sTLD)”Managed by private organizations representing a specific community.
.gov(US Government).edu(Accredited US institutions).aero(Aviation industry)
Infrastructure TLD
Section titled “Infrastructure TLD”.arpa: Managed by IANA, used exclusively for technical infrastructure (e.g., reverse DNS lookups).
Reserved TLDs
Section titled “Reserved TLDs”Per RFC 2606, four TLDs are permanently reserved for testing and documentation to avoid confusion in production environments:
.test.example.invalid.localhost