Definitions covering IP, DNS, routing, VPNs, privacy, phone lookups, and diagnostics.
Use this glossary while reading our guides and tool explainers. Search terms, scan by category, and jump directly to any entry with#term anchors when you want a stable reference.
Definitions covering IP, DNS, routing, VPNs, privacy, phone lookups, and diagnostics.
Filter terms by IP addressing, DNS, VPN access, infrastructure, security, hardware, and more.
Most entries connect directly to deeper explainers, live lookups, or related glossary terms.
A security method that requires two forms of verification (typically password + phone code) before granting access to an account.
A DNS record that maps a hostname to an IPv4 address.
A DNS record that maps a hostname to an IPv6 address.
A routing method where multiple servers share the same IP and the network routes users to the nearest one.
Address Resolution Protocol maps an IP address to a device's MAC address on a local network.
A number that identifies a network/operator on the internet (an autonomous system). ASNs help route traffic across networks (BGP).
The maximum data transfer rate of a network connection, measured in bits per second (bps). Higher bandwidth means more data can flow at once.
The routing protocol used between networks on the internet to exchange routes and reachability information.
The name and number information shown for an incoming call. Caller ID can be helpful, but it can also be spoofed by scam callers and robocall systems.
A large-scale NAT system used by ISPs that shares public IPv4 addresses across many customers using the 100.64.0.0/10 range (RFC 6598). It can block inbound connections and port forwarding.
A notation for IP ranges like 203.0.113.0/24. It indicates how many bits are fixed in a network prefix, defining the size of a subnet.
A DNS record that maps one hostname to another hostname (an alias).
A facility that houses servers, storage, networking equipment, and power/cooling systems used to run websites, cloud platforms, and internet services.
An attack that overwhelms a target network or service with traffic from many sources. Gamers and streamers sometimes use VPNs and router hardening to reduce DDoS exposure risks.
The local router address your device uses to reach other networks (including the internet). It is commonly something like 192.168.1.1 or 10.0.0.1 on home networks.
Dynamic Host Configuration Protocol automatically assigns IP addresses to devices on a network.
The system that maps domain names (example.com) to IP addresses so browsers can connect to websites.
A privacy issue where DNS queries bypass the VPN tunnel and go to ISP/public resolvers, revealing provider or location patterns even when your visible IP changes.
A DNS-based list used by email/security systems to flag IPs associated with spam or abuse. DNSBL checks help determine whether an IP may be blocked or filtered by receiving systems.
DNS Security Extensions add cryptographic signatures to DNS records to prevent tampering and spoofing.
A protocol that encrypts DNS queries inside HTTPS traffic, preventing ISPs and networks from seeing which domains you resolve. Supported by most modern browsers.
A protocol that encrypts DNS queries using TLS on port 853. Similar goal to DoH but operates as a dedicated encrypted DNS channel rather than piggybacking on HTTPS.
A network setup where traffic is translated by two routers/NAT devices (for example an ISP modem/router plus your own router). It can complicate gaming, port forwarding, and inbound connections.
A public IP address that can change over time, typically assigned by your ISP via DHCP.
The process of converting readable data into unreadable ciphertext using a key, so only authorized parties can decode it. Essential for VPNs, HTTPS, and secure messaging.
A wired networking standard (IEEE 802.3) using cables and switches for fast, reliable local network connections. Common speeds range from 100 Mbps to 10 Gbps.
A security system that monitors and filters network traffic based on defined rules, blocking unauthorized connections while allowing legitimate ones.
Low-level software running on hardware devices such as routers. Keeping firmware updated helps fix bugs, improve stability, and patch security issues.
A restriction that changes or blocks content based on your IP geolocation, DNS resolver location, account region, or payment country.
HyperText Transfer Protocol is the foundation of web communication. HTTPS adds TLS encryption for secure connections (the lock icon in browsers).
The global network of networks that connects devices, ISPs, data centers, mobile carriers, and cloud services using shared protocols and routing systems.
A numeric identifier for a device on a network. Public IPs are visible on the internet; private IPs are used inside local networks.
An estimate of where an IP address is located based on allocation data, routing patterns, and geolocation databases. It is not GPS and is usually city/region level at best.
The most common IP format using four numbers like 8.8.8.8. IPv4 space is limited, which is why IPv6 exists.
The shortage of available IPv4 addresses, which led to widespread use of NAT, CGNAT, and IPv6 adoption.
A newer IP format using hexadecimal groups like 2001:4860:4860::8888. It provides a much larger address space.
A company that provides your internet connection (home/mobile). Your public IP address is typically assigned by your ISP.
A network that connects devices within a limited area such as a home, office, or school using Ethernet cables or Wi-Fi.
The time it takes for data to travel from source to destination, usually measured in milliseconds (ms). Lower latency means faster response times.
A unique hardware identifier (48-bit) assigned to every network interface. MAC addresses operate at the link layer and are used for local network communication.
A network that spans a city or large campus, bridging the gap between LANs and WANs. Often uses fiber optic backbone.
A device that converts signals from your ISP (cable, fiber, DSL) into data your router and devices can use. The modem connects your home to the internet.
Multiprotocol Label Switching is a routing technique that directs data using short path labels rather than long network addresses, improving speed and traffic management.
A DNS record that specifies the mail server responsible for receiving email for a domain.
A technique that lets many private devices share one public IP address via a router. It's why devices inside your home network aren't directly reachable from the internet.
A DNS record that delegates a domain to specific authoritative name servers.
A long-established open-source VPN protocol known for flexibility and broad compatibility across desktop, mobile, and router setups.
A small unit of data transmitted over a network. Internet traffic is broken into packets that travel independently and are reassembled at the destination.
A networking problem where some packets never reach their destination. Packet loss can cause buffering, lag, poor call quality, and unstable VPN or gaming sessions.
A social engineering attack where fake emails, messages, or websites impersonate trusted entities to trick users into revealing passwords, payment details, or personal information.
A network utility that sends ICMP echo requests to test whether a host is reachable and measures round-trip latency in milliseconds.
A router feature that directs inbound traffic on a public IP/port to a specific device on a private network.
An internal network address (RFC1918) that is not routable on the public internet, such as 10.x.x.x or 192.168.x.x.
A standardized set of rules that devices follow to exchange data. TCP, IP, HTTP, TLS, DNS, and VPN protocols all define how internet traffic behaves.
A server that forwards your traffic. Proxies can change apparent IPs but often don't encrypt traffic like a VPN.
A DNS record used for reverse lookups: it maps an IP address back to a hostname. PTR records are commonly used by email servers and for diagnostics.
An IP address that is routable on the public internet. It's what websites see when you connect from home or mobile networks.
A modern, structured protocol used to retrieve registration and allocation data for domains and IP resources. RDAP is the successor to legacy WHOIS for many registries and internet registries.
A lookup that asks "what hostname is configured for this IP?". It typically uses a PTR record under in-addr.arpa (IPv4) or ip6.arpa (IPv6).
A device that forwards data packets between networks, directing traffic from your local network to the internet and back based on IP addresses.
Software-Defined Wide Area Network uses software to intelligently manage multiple WAN connections, improving performance and reducing costs for businesses.
A system that stores data, runs applications, or answers requests from other devices called clients. Websites, APIs, and email all depend on servers.
A DNS-based service that reroutes specific requests so streaming and geo-restricted apps see a different region without encrypting your full device traffic.
A versatile proxy protocol that routes any type of traffic (not just HTTP) through a proxy server. SOCKS5 supports authentication but does not encrypt traffic by default.
A VPN feature that routes only selected apps or traffic through the VPN while other traffic uses the normal internet connection. Misconfigured split tunneling can cause leaks or inconsistent results.
Service Set Identifier is the name of a Wi-Fi network that appears when you scan for available connections.
A public IP address that stays the same over time. Often required for hosting services or consistent remote access.
Session Traversal Utilities for NAT is a protocol used by WebRTC and other apps to discover network path information. STUN behavior is one reason WebRTC leak tests matter for VPN users.
A logical subdivision of an IP network. Subnetting splits a larger network into smaller segments for better organization, security, and routing efficiency.
A network device that connects devices within a LAN and forwards data based on MAC addresses. Switches are more efficient than hubs because they send data only to the intended recipient.
A reliable, connection-oriented protocol that ensures data arrives completely and in order. Used for web browsing, email, and file transfers.
The actual amount of data successfully transferred over a network in a given time period. Unlike bandwidth, throughput accounts for overhead and packet loss.
A regional time setting (for example, Europe/Chisinau or America/New_York). IP tools estimate timezone from IP geolocation data, so it may differ from your device clock settings.
A cryptographic protocol that provides encrypted communication over networks. TLS is the security layer behind HTTPS, email encryption, and VPN protocols.
A privacy network that routes traffic through three encrypted relays so no single node sees both sender and destination. Significantly slower than VPNs.
A network diagnostic tool that shows the path packets take from your device to a destination, listing each hop and its latency.
A DNS cache duration (in seconds) that tells resolvers how long to keep a record before refreshing it.
A DNS record that stores text values, often used for domain verification and email security records such as SPF, DKIM, and DMARC.
A faster but less reliable protocol that sends data without guaranteeing delivery or order. Used for streaming, gaming, and VoIP.
A calling technology that routes phone conversations over internet connections instead of traditional phone lines. VoIP numbers are common in business systems and scam campaigns.
A Virtual Private Network encrypts your traffic and routes it through a VPN server, helping reduce tracking and protect data on untrusted networks.
A VPN safety feature that blocks internet traffic if the VPN tunnel drops unexpectedly, helping prevent accidental IP exposure.
A network that connects LANs across large geographic distances — cities, countries, or continents. The internet is the largest WAN.
Web Real-Time Communication is a browser technology for real-time audio/video/data connections. Depending on browser behavior and settings, WebRTC can expose IP-related information through STUN requests.
A protocol/service used to retrieve registration information for domains and allocation/ownership info for IP address ranges. It's not the same as IP geolocation.
A family of wireless networking protocols (IEEE 802.11) that let devices connect to a local network without cables. Wi-Fi is not the same as the internet.
A modern VPN protocol designed to be lean, fast, and easier to audit than older VPN stacks. Many current VPNs use WireGuard for better speed and lower overhead.
Wi-Fi Protected Access is a series of security protocols that encrypt wireless network traffic. WPA3 is the latest and most secure standard.
A router feature designed to simplify Wi-Fi device setup (often using a button or PIN). Many users disable WPS for security and control reasons.