Learn: IP addresses, privacy and networking
Plain-language guides to IP addresses, VPNs, DNS, proxies and home networking, written by the people who build the tools on this site. Each guide ends with the tool that lets you check the thing it explains.
Privacy & VPN
What is a VPN? What a VPN does and does not protect, how it changes your IP address, when it is worth using and how to test it for leaks. 9 min read · Updated Oct 21, 2026 Is public Wi-Fi safe? The real risks of public Wi-Fi in cafés, hotels and airports, and seven practical steps to keep your accounts and data safe. 8 min read · Updated Oct 21, 2026 How to change your IP address Change your public IP by restarting the router, using a VPN or switching to mobile data, or set a new local IP on Windows, Mac, iPhone and Android. 8 min read · Updated Oct 21, 2026 How to hide your IP address Six ways to hide your IP address compared: VPN, proxy, Tor, iCloud Private Relay, mobile data and public Wi-Fi. Steps per device and how to test for leaks. 9 min read · Updated Oct 21, 2026 What can someone do with your IP address? What a stranger can really do with your IP address (approximate location, DDoS, port scans), what they cannot (your name or street), and how to protect it. 9 min read · Updated Oct 21, 2026 What is a proxy server? A proxy server forwards your traffic so websites see its address instead of yours. How HTTP, SOCKS5, residential and datacenter proxies differ from a VPN. 8 min read · Updated Oct 21, 2026 What is a user agent, and what does yours say about you? A user agent is the string your browser sends with every request to say what it is. See yours, decode each token, and why browsers now freeze most of it. 6 min read · Updated Oct 21, 2026 What is an IP ban, and how do you know if you have one? An IP ban blocks every connection from your address, not just your account. How to tell it from an account ban, why shared IPs get caught, how to fix it. 7 min read · Updated Oct 21, 2026 What is browser fingerprinting, and how do you test yours? Browser fingerprinting identifies you from canvas, fonts, GPU, screen and other signals, no cookies needed. How it works, how unique you are, what helps. 9 min read · Updated Oct 21, 2026 What is IP spoofing? IP spoofing means packets with a forged source address. How it works, the DDoS attacks it enables, why BCP 38 filtering stops it, and why it is not a VPN. 7 min read · Updated Oct 21, 2026 What is WebRTC, and why can it leak your IP address? WebRTC powers browser calls but can hand websites your real IP even behind a VPN. How the leak works, how to test for it and how to limit it per browser. 9 min read · Updated Oct 21, 2026 Why is my IP blacklisted, and how do I get it removed? Why an IP lands on a spam or abuse blacklist, how to check the major lists, and delisting steps for Spamhaus, SpamCop, Barracuda, Microsoft and UCEPROTECT. 8 min read · Updated Oct 21, 2026
Find your IP
What is an IP address? What an IP address is, how it works, the difference between IPv4 and IPv6, public and private, static and dynamic – with examples. 8 min read · Updated Oct 21, 2026 How to find your IP address on any device Step-by-step: find your public and local IP address on Windows, Mac, iPhone, Android, Linux, Chromebook, your router, TV, console and printer. 8 min read · Updated Oct 21, 2026 IPv4 vs IPv6: what is the difference? How IPv4 and IPv6 differ in format, size, speed and security, why both still exist, and how to check which one you are using. 9 min read · Updated Oct 21, 2026 Public vs private IP addresses The difference between public and private IP addresses, the RFC 1918 private ranges, and how NAT connects them to the internet. 9 min read · Updated Oct 21, 2026 127.0.0.1 and localhost explained 127.0.0.1 and localhost mean this computer. How loopback works, how it differs from 0.0.0.0 and your LAN IP, and how to fix localhost refused to connect. 7 min read · Updated Oct 21, 2026 CIDR notation explained How CIDR notation works, what /24, /32 and 255.255.255.0 mean, a chart of IPv4 prefix lengths with masks and host counts, and how IPv6 prefixes differ. 8 min read · Updated Oct 21, 2026 How to find a printer's IP address Find your printer's IP address from its control panel, a printed network page, Windows, macOS or your router, with steps for HP, Canon, Epson and Brother. 8 min read · Updated Oct 21, 2026 How to find your IP address on a Mac Find your Mac's local IP address in System Settings or Terminal (ipconfig getifaddr en0), see your public IP in one click, and check whether it has IPv6. 6 min read · Updated Oct 21, 2026 How to find your IP address on Android Find your Android phone's IP address on Samsung, Pixel and Xiaomi: the Wi-Fi settings path, the mobile data address, the router's IP and your public IP. 6 min read · Updated Oct 21, 2026 How to find your IP address on iPhone Find your iPhone's IP address in Settings Wi-Fi, see your public IP in one tap, get the cellular address iOS hides, and see how Private Relay changes it. 7 min read · Updated Oct 21, 2026 How to find your IP address on Windows 11 and Windows 10 Find your IP address on Windows 11 or 10 via Settings, ipconfig in Command Prompt or PowerShell, and tell your local 192.168 address from the public one. 6 min read · Updated Oct 21, 2026 How to trace an IP address Trace an IP address step by step: pull it from email headers or logs, look up its owner, location and route, and see what an IP can and cannot reveal. 9 min read · Updated Oct 21, 2026 IP address classes The five IPv4 address classes with ranges, leading bits and default masks, why CIDR replaced classful addressing in 1993, and where classes still matter. 7 min read · Updated Oct 21, 2026 Static vs dynamic IP addresses Static and dynamic IP addresses compared: how DHCP leases work, why your IP keeps changing, how to check which you have, and when a static IP is worth it. 8 min read · Updated Oct 21, 2026 What a 169.254 IP address means A 169.254.x.x address means your device asked the router for an IP and got no answer. What APIPA is, why it happens, the fixes, and 169.254.169.254. 7 min read · Updated Oct 21, 2026 What is a subnet mask? A subnet mask tells a device which part of an IP address is the network and which is the host. What 255.255.255.0 and /24 mean, plus a CIDR cheat sheet. 7 min read · Updated Oct 21, 2026 Why is my IP location wrong? Why websites put you in the wrong city, state or country, how accurate IP geolocation really is, and how to get your IP location corrected at the source. 7 min read · Updated Oct 21, 2026
Home network
How to choose a wireless router What to look for in a home Wi-Fi router – Wi-Fi standards, mesh, ports, IPv6, VPN support and security updates – in plain English. 9 min read · Updated Oct 21, 2026 192.168.1.1 router login How to open the 192.168.1.1 router login page, default usernames and passwords for TP-Link, Netgear, ASUS and Linksys, and fixes when it will not load. 7 min read · Updated Oct 21, 2026 Common port numbers A reference list of common TCP and UDP ports for web, mail, remote access, file sharing, databases and games: what each is for and which to keep closed. 8 min read · Updated Oct 21, 2026 How to find your router's IP address Find your router's IP address (default gateway) on Windows, Mac, iPhone, Android and Linux, plus factory addresses for TP-Link, Netgear and ASUS. 7 min read · Updated Oct 21, 2026 What is a default gateway, and how do you find yours? A default gateway is the router address your device sends traffic to for anything outside your network. How it differs from your IP and how to find it. 6 min read · Updated Oct 21, 2026 What is a MAC address? A MAC address is the hardware identifier of a network interface: how it differs from an IP, how to find yours on any device and why phones randomize it. 8 min read · Updated Oct 21, 2026 What is CGNAT, and how do you know if you are behind it? Carrier-grade NAT means your ISP shares one public IP among many customers. What CGNAT is, how to check for it, what it breaks and the ways around it. 8 min read · Updated Oct 21, 2026 What is NAT? How NAT lets every device in your home share one public IP, what open, moderate and strict NAT types mean for gaming, and where port forwarding fits in. 8 min read · Updated Oct 21, 2026 What is port forwarding, and how do you set it up? Port forwarding lets internet connections reach one device on your home network. When you need it, how to set it up on any router, and how to test it. 8 min read · Updated Oct 21, 2026
Gaming & speed
What is packet loss, and how do you fix it? Packet loss is the share of packets that never arrive: what causes it, how to measure it on PC, Xbox or PS5, and fixes for Wi-Fi, cables and ISP faults. 8 min read · Updated Oct 21, 2026 What is ping, and what is a good ping for gaming? Ping is the round-trip time between your device and a server in milliseconds. What counts as good ping for gaming, how to test it and what lowers it. 8 min read · Updated Oct 21, 2026
DNS
How to flush your DNS cache Flush your DNS cache with one command: ipconfig /flushdns on Windows 11, the mDNSResponder command on macOS, resolvectl on Linux, plus Chrome and phones. 7 min read · Updated Oct 21, 2026 What is a DNS leak? A DNS leak sends your lookups to your ISP even with a VPN on, exposing every site you visit. What causes it, how to test for one, and the fix per platform. 8 min read · Updated Oct 21, 2026 What is Private DNS on Android? Private DNS encrypts your Android phone's DNS lookups. How it works, how to turn it on, which hostname to use and the fix for the cannot be accessed error. 7 min read · Updated Oct 21, 2026