Web infrastructure glossary
Clear definitions for domain names, DNS, web hosting, servers, HTTPS, email, networking, and web technology.
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Eight foundational terms that connect the rest of the glossary.
- Content delivery network (CDN) A content delivery network (CDN) serves cached or proxied content from a distributed network of locations.
- Domain name A domain name is a human-readable name used to identify an Internet destination, such as example.com.
- Domain Name System (DNS) The Domain Name System (DNS) is the distributed system that publishes and resolves names used by Internet services.
- HTTPS HTTPS is HTTP exchanged over a connection protected by Transport Layer Security (TLS).
- IP address (IP) An IP address is a numerical identifier used to address a network interface with the Internet Protocol.
- Shared hosting Shared hosting is a hosting model where multiple customer websites use a provider-managed server platform.
- Simple Mail Transfer Protocol (SMTP) Simple Mail Transfer Protocol (SMTP) is the standard protocol used to submit and relay email messages.
- SSL certificate An SSL certificate is the common name for a digital certificate used to authenticate a hostname during TLS.
All glossary terms
A
- A record Domains & DNS An A record is a DNS record that maps a hostname to an IPv4 address.
- AAAA record Domains & DNS An AAAA record is a DNS record that maps a hostname to an IPv6 address.
- Application programming interface (API) Web & Development An application programming interface (API) is a defined way for software systems to exchange requests and data.
- Authoritative nameserver Domains & DNS An authoritative nameserver is a DNS server that publishes the source records for a DNS zone.
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- Cache Performance & CDN A cache stores a reusable copy of data so later requests can be served more quickly.
- Certificate authority (CA) Security & Encryption A certificate authority (CA) is an organization trusted to issue and sign digital certificates.
- Certificate signing request (CSR) Security & Encryption A certificate signing request (CSR) is a signed request containing a public key and identifying information for a new certificate.
- Cipher Security & Encryption A cipher is an algorithm that transforms readable data into protected data and back when the correct key is available.
- CNAME record (CNAME) Domains & DNS A CNAME record is a DNS record that makes one hostname an alias of another hostname.
- Content delivery network (CDN) Performance & CDN A content delivery network (CDN) serves cached or proxied content from a distributed network of locations.
- Content management system (CMS) Web & Development A content management system (CMS) is software used to create, organize, and publish website content.
- Control panel Hosting & Servers A hosting control panel is a web interface for managing common website, domain, email, database, and account tasks.
D
- Database Web & Development A database is an organized collection of data managed so applications can store, retrieve, and update information.
- Dedicated server Hosting & Servers A dedicated server is a physical server assigned to one customer or workload rather than shared as separate virtual servers.
- Distributed denial-of-service attack (DDoS) Security & Encryption A distributed denial-of-service (DDoS) attack floods a target with traffic from many sources to make it slow or unreachable.
- DNS propagation Domains & DNS DNS propagation is the transition period after a DNS change, while cached answers expire unevenly across resolvers.
- DNS record Domains & DNS A DNS record is a structured entry that publishes information about a name in the Domain Name System.
- Domain name Domains & DNS A domain name is a human-readable name used to identify an Internet destination, such as example.com.
- Domain Name System (DNS) Domains & DNS The Domain Name System (DNS) is the distributed system that publishes and resolves names used by Internet services.
- Domain registrar Domains & DNS A domain registrar is a company authorized to register and manage domain names for customers.
- Domain registry Domains & DNS A domain registry is the organization that operates a top-level domain and maintains its master database of registrations.
- Domain transfer Domains & DNS A domain transfer moves a domain name's sponsorship from one registrar to another.
- Domain-based Message Authentication, Reporting, and Conformance (DMARC) Email & Communication DMARC is an email-authentication policy that uses SPF and DKIM results plus domain alignment to guide message handling.
- DomainKeys Identified Mail (DKIM) Email & Communication DomainKeys Identified Mail (DKIM) lets a sending domain add a cryptographic signature to an email message.
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- HTTP redirect Web & Development An HTTP redirect is a server response that tells the client to fetch a different URL instead.
- HTTP status code Web & Development An HTTP status code is a three-digit value that summarizes the result of an HTTP request.
- HTTP Strict Transport Security (HSTS) Security & Encryption HTTP Strict Transport Security (HSTS) is a web security policy that tells browsers to use HTTPS for a host.
- HTTPS Security & Encryption HTTPS is HTTP exchanged over a connection protected by Transport Layer Security (TLS).
- Hypertext Markup Language (HTML) Web & Development Hypertext Markup Language (HTML) is the standard markup language used to structure content on web pages.
- Hypertext Transfer Protocol (HTTP) Web & Development Hypertext Transfer Protocol (HTTP) defines how clients and servers exchange requests and responses on the web.
I
- Internet Message Access Protocol (IMAP) Email & Communication Internet Message Access Protocol (IMAP) lets an email client access and manage messages stored on a mail server.
- IP address (IP) Networking & IP An IP address is a numerical identifier used to address a network interface with the Internet Protocol.
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L
- Latency Performance & CDN Latency is the delay between an action or request and the corresponding response or data transfer.
- Let's Encrypt Security & Encryption Let's Encrypt is a nonprofit certificate authority that issues publicly trusted TLS certificates through an automated process.
- Load balancer Performance & CDN A load balancer distributes incoming requests or connections across multiple service instances.
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S
- Secure Shell (SSH) Security & Encryption Secure Shell (SSH) is a protocol for authenticated, encrypted access to remote systems and services.
- Sender Policy Framework (SPF) Email & Communication Sender Policy Framework (SPF) lets a domain publish which sending systems are authorized for its email envelope domain.
- Server Hosting & Servers A server is software or a computer that provides data or services to other systems called clients.
- Shared hosting Hosting & Servers Shared hosting is a hosting model where multiple customer websites use a provider-managed server platform.
- Simple Mail Transfer Protocol (SMTP) Email & Communication Simple Mail Transfer Protocol (SMTP) is the standard protocol used to submit and relay email messages.
- SSH File Transfer Protocol (SFTP) Web & Development SSH File Transfer Protocol (SFTP) is a file transfer and management protocol that runs inside an SSH connection.
- SSL certificate Security & Encryption An SSL certificate is the common name for a digital certificate used to authenticate a hostname during TLS.
- Subdomain Domains & DNS A subdomain is a domain name that sits below another domain in the DNS hierarchy.
T
- Time to live (TTL) Domains & DNS In DNS, time to live (TTL) is the number of seconds a record may be cached before it should be refreshed.
- Top-level domain (TLD) Domains & DNS A top-level domain (TLD) is the label at the highest visible level of a domain name, such as .com or .org.
- Transport Layer Security (TLS) Security & Encryption Transport Layer Security (TLS) is a protocol that protects network communication with encryption, integrity checks, and authentication.
- TXT record Domains & DNS A TXT record is a DNS record that publishes text at a name, most often for verification and email authentication.
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V
- Virtual machine (VM) Hosting & Servers A virtual machine (VM) is an isolated computing environment that emulates a computer on shared physical hardware.
- Virtual private server (VPS) Hosting & Servers A virtual private server (VPS) is a virtual machine sold as an independently administered server environment.
W
- Web hosting Hosting & Servers Web hosting is a service that provides the computing, storage, network access, and software environment needed to publish a website.
- WHOIS Domains & DNS WHOIS is a long-standing query system for looking up registration data associated with Internet resources such as domain names.
- WordPress Web & Development WordPress is open-source content management software used to create and manage websites.