Networking & DNSAlso called: "tld", "domain extension", "domain suffix"
TLDs are the highest level in the DNS hierarchy, managed by ICANN.
TLD categories
- Generic TLDs (gTLDs): .com, .net, .org, .info, .biz
- Originally intended for specific purposes, now generally available.
- Most common and widely recognized worldwide.
- Country Code TLDs (ccTLDs): .us, .uk, .de, .jp, .au
- Two-letter codes representing countries/territories (ISO 3166-1).
- Subject to local registration rules and restrictions.
- New gTLDs: .app, .dev, .tech, .cloud, .ai, .io
- Introduced since 2013 to expand namespace.
- Often industry-specific or descriptive.
- Sponsored TLDs: .gov, .edu, .mil, .museum
- Restricted to specific organizations or purposes.
- Require verification and eligibility proof.
- Infrastructure TLD: .arpa
- Used for Internet infrastructure (reverse DNS).
TLD importance
- Brand identity: .tech for tech companies, .store for e-commerce.
- Geographic targeting: .uk for UK businesses, .nyc for New York.
- SEO impact: ccTLDs signal geographic relevance to search engines.
- Trust perception: .edu and .gov have high trust, .xyz often lower.
- Cost variation: .com costs $10-15/year, premium TLDs $20-100+.
Security considerations
- Typosquatting: Attackers register similar domains with different TLDs.
- Homograph attacks: Unicode lookalike characters in internationalized TLDs.
- Brand protection: Register key TLD variants to prevent abuse.
- Monitoring: Track TLD variations for phishing and fraud.
ICANN governance
- Coordinates global DNS system.
- Approves new TLD applications.
- Manages root zone file.
- Sets policies for registrars and registries.
- Resolves disputes (UDRP process).
Popular TLDs
- .com: 160M+ registrations (most popular).
- .cn: 20M+ (China country code).
- .tk: 18M+ (Tokelau, free registrations).
- .de: 17M+ (Germany).
- .net: 13M+ (networks/technology).