Domain & DNS Glossary

RDAP →

The modern, standardized protocol for querying domain registration data, replacing the legacy WHOIS system with structured JSON responses.

WHOIS →

The legacy protocol for querying domain registration information, returning unstructured text data about domain ownership and status.

DNS →

The internet's hierarchical naming system that translates human-readable domain names into IP addresses that computers use to communicate.

CDN →

Content Delivery Network.

DNS Propagation →

The time it takes for DNS changes to spread across all DNS servers worldwide.

DNS Zone →

A portion of the DNS namespace that is managed by a specific organization or administrator.

FQDN →

Fully Qualified Domain Name.

HTTPS →

Hypertext Transfer Protocol Secure.

IANA →

Internet Assigned Numbers Authority.

IP Address →

Internet Protocol Address.

IPv6 →

Internet Protocol version 6.

Latency →

The time delay between a request and response, typically measured in milliseconds.

Security Headers →

HTTP response headers that enhance website security by controlling browser behavior.

SSL Certificate →

Secure Sockets Layer certificate.

TTL →

Time To Live.

Unicode →

A computing standard for consistent encoding and handling of text in most world writing systems.

URL →

Uniform Resource Locator.

Wildcard DNS →

A DNS record that matches requests for non-existent subdomains.

Wildcard SSL →

An SSL certificate that secures a domain and all its first-level subdomains with a single certificate.

Zone File →

A text file that contains all the DNS records for a domain.

HTTP/2 →

A major revision of HTTP that introduces multiplexing, header compression, and improved performance over HTTP/1.1.

HTTP/3 →

The latest HTTP version built on the QUIC transport protocol, improving connection setup and loss recovery.

IPv4 →

The original internet protocol addressing scheme using 32-bit addresses like 192.0.2.1.

DNS Resolver →

A server that receives DNS queries from clients and retrieves the answers by querying authoritative servers.

Recursive DNS →

The process where a resolver queries multiple DNS servers on behalf of a client until it returns a final answer.

Authoritative Nameserver →

A DNS server that holds the definitive records for a domain and answers queries with authoritative data.

DNS Cache →

Temporary storage of DNS query results by resolvers or clients to speed up repeated lookups.

MAC Address →

A unique hardware identifier assigned to network interface controllers for communications on a network segment.

Web Server →

Software and hardware that serves web content to clients over HTTP/HTTPS protocols.

TLD →

The last segment of a domain name (e.g., .com, .org, .io), representing the highest level in the DNS hierarchy after the root.

gTLD →

A category of TLDs not tied to a specific country, including classic extensions like .com and .org, plus newer ones like .app and .dev.

ccTLD →

A two-letter TLD assigned to a specific country or territory, like .uk for the United Kingdom or .de for Germany.

IDN →

A domain name containing non-ASCII characters like Chinese, Arabic, or Cyrillic scripts, enabling native language web addresses.

Punycode →

An encoding system that converts Unicode domain names to ASCII-compatible format, enabling internationalized domain names to work with DNS.

Addon Domain →

A fully functional domain hosted on the same hosting account as your primary domain.

Brandable Domain →

A domain name that is short, memorable, and easy to pronounce, making it suitable for building a brand.

Bulk Domain Checker →

A tool or API that allows you to check the availability of multiple domain names simultaneously.

Domain Availability →

The status indicating whether a domain name is currently unregistered and available for purchase.

Domain Extension →

The suffix of a domain name that appears after the dot, such as .com, .org, or .net.

Domain Flipping →

The practice of buying domain names at low prices and selling them for profit.

Domain Forwarding →

Also called domain redirect or URL forwarding.

Domain Hack →

A creative use of a domain extension as part of the domain name to spell out a word or phrase.

Domain Masking →

A type of domain forwarding where the URL in the browser address bar remains the forwarded domain rather than showing the destination URL.

Domain Name →

A human-readable address used to identify a location on the internet.

Domain Renewal →

The process of extending your domain registration before it expires.

Domain Valuation →

The process of estimating the market value of a domain name.

EMD →

Exact Match Domain.

Generic Domain →

A domain name consisting of a common English word or phrase, such as cars.com or hotels.com.

Geo-Domain →

A domain name that includes a geographic location, such as a city, state, or country name.

Hostname →

A label assigned to a device connected to a network.

Keyword Domain →

A domain name that contains one or more relevant keywords related to a specific industry or topic.

Landing Page Domain →

A domain name specifically chosen for marketing campaigns or landing pages.

PMD →

Partial Match Domain.

Redirect →

A technique that automatically forwards visitors from one URL to another.

SEO →

Search Engine Optimization.

Short Domain →

A domain name with very few characters, typically under 5-6 letters.

SLD →

Second-Level Domain.

Subdomain →

A domain that is part of a larger domain, created by adding a prefix to the main domain name.

Type-In Traffic →

Website visitors who arrive by typing the domain name directly into their browser address bar.

Vanity URL →

A customized, memorable URL that typically redirects to a longer or more complex destination URL.

Web Hosting →

A service that provides server space and resources for websites to be accessible on the internet.

Domain Alias →

A secondary domain that points to the same website or content as another domain.

Username →

A unique identifier used to authenticate and identify users on digital platforms and services.

A Record →

A DNS record that maps a domain name to an IPv4 address, enabling browsers to find the server hosting a website.

AAAA Record →

A DNS record that maps a domain name to an IPv6 address, the modern successor to IPv4 A records.

CNAME Record →

A DNS record that creates an alias pointing one domain name to another, commonly used for subdomains and CDN configuration.

MX Record →

A DNS record that specifies which mail servers should receive email for a domain, enabling email delivery.

TXT Record →

A DNS record that stores text data, commonly used for email authentication (SPF, DKIM, DMARC), domain verification, and other purposes.

Name Server →

A DNS server authoritative for a domain, specified by NS records that delegate control to specific servers.

NS Record →

Nameserver record.

SOA Record →

Start of Authority record.

SPF Record →

Sender Policy Framework record.

Glue Record →

An A or AAAA record stored at the parent zone to prevent circular dependencies when a nameserver is inside the domain.

SPF →

An email authentication protocol that specifies which mail servers are authorized to send email on behalf of a domain.

DKIM →

An email authentication method that adds a digital signature to outgoing emails, allowing receivers to verify the message was not altered.

DMARC →

An email authentication protocol that builds on SPF and DKIM, allowing domain owners to specify how unauthenticated email should be handled.

SSL/TLS →

Cryptographic protocols that encrypt communication between web servers and browsers, indicated by HTTPS and the padlock icon.

HSTS →

A security header that forces browsers to only connect to a website over HTTPS, preventing downgrade attacks.

CAA Record →

A DNS record that specifies which Certificate Authorities are allowed to issue SSL/TLS certificates for a domain.

Domain Health →

A measure of how well a domain is configured for security, email deliverability, and overall technical performance.

Email →

Electronic mail, a method of exchanging messages between people using electronic devices.

Email Authentication →

Technical standards and protocols used to verify that an email genuinely comes from the claimed sender.

Email Deliverability →

The ability of emails to successfully reach recipients' inboxes rather than being filtered as spam.

Email Security →

Measures and protocols used to protect email communications from threats like phishing, spoofing, and interception.

Reverse DNS →

A DNS query that converts an IP address to a domain name, the opposite of a standard DNS lookup.

TLS →

Transport Layer Security.

Catch-All Email →

An email setup that routes all addresses at a domain to a single inbox, even if the address does not exist.

Bounce Address →

The return address used for non-delivery reports (bounces) when email cannot be delivered.

Email Forwarding →

A mail routing setup that forwards incoming messages from one address to another.

Domain Registrar →

A company accredited to sell domain names to the public, acting as an intermediary between domain registrants and registries.

Domain Registry →

An organization that manages the database of all domain names registered under a specific TLD, like Verisign for .com.

Domain Registrant →

The individual or organization that registers and owns a domain name, holding legal rights to use that domain.

ICANN →

The non-profit organization that coordinates the global domain name system, IP addresses, and protocol parameters.

EPP Status Codes →

Standardized codes indicating the current state of a domain, such as whether it can be transferred, deleted, or modified.

Domain Lifecycle →

The stages a domain passes through from registration to expiration, including active, grace period, redemption, and deletion phases.

Aftermarket Domain →

A domain name that was previously registered and is now being sold by its owner on a secondary marketplace.

Auth Code →

Also known as EPP code, transfer code, or authorization code.

Auto-Renewal →

A service offered by domain registrars that automatically renews your domain registration before it expires.

Backorder →

A service that allows you to automatically attempt to register a domain name as soon as it becomes available after expiration.

Domain Auction →

A marketplace where domain names are sold to the highest bidder.

Domain Broker →

A professional who negotiates the purchase or sale of domain names on behalf of clients.

Domain Expiration →

The date when a domain registration period ends.

Domain Investing →

The practice of acquiring domain names as investments with the expectation of selling them for profit.

Domain Parking →

Registering a domain name without associating it with an active website.

Domain Portfolio →

A collection of domain names owned by an individual or organization.

Domain Registration →

The process of acquiring a domain name from a registrar for a specified period (typically 1-10 years).

Domain Transfer →

The process of moving a domain name from one registrar to another.

Drop Catching →

The practice of registering a domain name the moment it becomes available after expiration.

EPP →

Extensible Provisioning Protocol.

Expired Domain →

A domain name whose registration period has ended and was not renewed.

Grace Period →

A period after domain expiration (typically 0-45 days depending on the TLD) during which the original registrant can still renew the domain at standard rates.

LLL Domain →

A three-letter domain name, such as abc.com or xyz.net.

LLLL Domain →

A four-letter domain name.

New gTLD →

Generic Top-Level Domains introduced after 2012 as part of ICANN's gTLD expansion program.

Parked Domain →

A registered domain name that is not actively used for a website or email.

Pending Delete →

The final status before an expired domain is released for public registration.

Premium Domain →

A high-value domain name that commands a price significantly above standard registration fees.

Redemption Period →

A period after the grace period (typically 30 days) during which a domain can still be recovered by the original registrant, but at a significantly higher fee.

Registry Lock →

A security feature that requires additional authentication steps before making changes to critical domain settings.

Reseller →

A company or individual that sells domain registrations on behalf of an accredited registrar.

Transfer Lock →

A domain status that prevents unauthorized transfers to another registrar.

UDRP →

Uniform Domain-Name Dispute-Resolution Policy.

Registrar Lock →

A registrar-level setting that prevents unauthorized domain transfers by locking the domain at the registrar.

Vanity Nameserver →

A branded nameserver hostname (e.g., ns1.yourbrand.com) used instead of default provider names.

Domain Value →

The estimated monetary worth of a domain name based on factors like length, keywords, extension, and market demand.

Anycast DNS →

A network addressing and routing method where DNS queries are routed to the nearest or best-performing server.

Brand Protection →

Strategies and services used to protect a company's brand online, including monitoring for typosquatting, cybersquatting, trademark infringement, and registering defensive domain names across multiple TLDs.

Cybersquatting →

The practice of registering domain names that contain trademarks or brand names with the intent to profit from their sale to the rightful trademark owner.

Domain Privacy →

Also called WHOIS privacy or ID protection.

Domain Squatting →

Registering domain names in bad faith to profit from someone else's trademark or brand.

Homoglyph Attack →

A type of phishing attack using domain names with characters that look similar to legitimate characters, such as using "rn" to look like "m" or using Cyrillic characters that resemble Latin letters.

Phishing →

A type of cyber attack where attackers create fake websites that mimic legitimate ones to steal user credentials, financial information, or personal data.

Sunrise Period →

An initial registration period for new TLDs where trademark holders can register domains before general availability.

Trademark →

A legally protected word, phrase, symbol, or design that identifies and distinguishes a brand.

Typosquatting →

The practice of registering domain names that are common misspellings or typos of popular domains.

DNSSEC →

An extension to DNS that adds cryptographic signatures to DNS data, helping prevent spoofing and cache poisoning attacks.

Registry Lock →

A higher-security lock applied at the registry level that requires manual verification to make critical changes.

Domain Spoofing →

An attack where a malicious actor impersonates a legitimate domain to deceive users or systems.

DNS Flood →

A denial-of-service attack that overwhelms DNS infrastructure with excessive queries.