IP & Networking Glossary

An ASN (Autonomous System Number) is a unique identifier assigned to networks on the internet. Large organizations like ISPs, universities, and companies have their own ASNs. ASNs are used in BGP routing to identify networks.

An IP blacklist (also called DNSBL or RBL) is a database of IP addresses that have been reported for sending spam, malware, or other abusive behavior. Email servers and websites use blacklists to filter incoming traffic.

DNS (Domain Name System) is a hierarchical naming system that translates human-readable domain names (like whatismyip.io) into IP addresses that computers use to identify each other. It's often called the "phonebook of the internet."

A DNS leak occurs when DNS queries are sent to your ISP's DNS servers instead of your VPN's servers, even while connected to a VPN. This reveals which websites you're visiting to your ISP, compromising your privacy.

HTTPS (Hypertext Transfer Protocol Secure) is the secure version of HTTP. It uses TLS/SSL encryption to protect data transmitted between your browser and websites. HTTPS prevents eavesdropping and tampering with your web traffic.

An IP (Internet Protocol) address is a unique numerical label assigned to each device connected to a computer network. It serves two main functions: identifying the host/network interface, and providing the location of the host in the network.

IPv4 (Internet Protocol version 4) is the fourth version of the Internet Protocol. It uses 32-bit addresses, written as four decimal numbers separated by periods (e.g., 192.168.1.1). IPv4 can support approximately 4.3 billion unique addresses.

IPv6 (Internet Protocol version 6) is the most recent version of the Internet Protocol. It uses 128-bit addresses, written as eight groups of hexadecimal numbers (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334). IPv6 was developed to address IPv4 exhaustion.

An ISP (Internet Service Provider) is a company that provides customers with access to the internet. ISPs may also provide related services such as email, web hosting, and domain registration. Your ISP assigns your IP address and can see your internet activity.

NAT (Network Address Translation) is a method of remapping IP address space into another. It's commonly used in home routers to allow multiple devices to share a single public IP address. NAT helps conserve IPv4 addresses and provides some security by hiding internal IPs.

A port is a numbered endpoint for network communication. Ports allow a single IP address to handle multiple services (e.g., web server on port 80, email on port 25). Port numbers range from 0 to 65535.

A private IP address is used within private networks and is not directly reachable from the internet. Common ranges include 192.168.x.x, 10.x.x.x, and 172.16-31.x.x. Private IPs are translated to public IPs via NAT when accessing the internet.

A proxy server acts as an intermediary between your device and the internet. When you use a proxy, websites see the proxy's IP address instead of yours. Unlike VPNs, most proxies don't encrypt traffic.

A PTR (Pointer) record is a DNS record used for reverse DNS lookups. It maps an IP address to a hostname, which is the opposite of an A record. PTR records are important for email server authentication and network diagnostics.

A public IP address is an IP address that is globally unique and reachable from the internet. It's assigned by your ISP and is what websites see when you connect to them. Public IPs are required for hosting servers or services accessible from the internet.

Tor (The Onion Router) is a free, open-source software that enables anonymous communication. It directs internet traffic through a worldwide network of relays, making it extremely difficult to trace. Tor is used for privacy, circumventing censorship, and accessing .onion sites.

A VPN (Virtual Private Network) creates an encrypted tunnel between your device and a VPN server. This hides your real IP address, encrypts your traffic, and can help bypass geo-restrictions. VPNs are commonly used for privacy and security.

WebRTC (Web Real-Time Communication) is a browser technology that enables video calls, voice chat, and file sharing without plugins. However, WebRTC can leak your real IP address even when using a VPN, making it a privacy concern.

WHOIS is a query and response protocol used to look up information about registered domain names and IP addresses. It provides details like the owner, registration date, and contact information for network resources.