Home / Learn
Learn how the internet sees you
Short, accurate guides on IP addresses, DNS, privacy and home networking. Each one links to a free tool so you can try it on your own connection.
How to Find Your IP Address on Any DeviceFind your public and private IP address on Windows, Mac, iPhone, Android and Linux, with the exact steps for each.6 min readWhat Is an IP Address? A Plain-English GuideAn IP address is how devices find each other on the internet. Learn what it is, what it reveals about you, and how to see yours.5 min readHow to Hide Your IP Address on Any Device: 5 MethodsLearn how to hide your IP address on PC, iPhone and Android with a VPN, Tor, a proxy or Private Relay. Compare each method and test that it worked.7 min readIPv4 vs IPv6: What's the Difference and Does It Matter?IPv4 and IPv6 are the two versions of the Internet Protocol. See how they differ, why IPv6 exists, and which one you are using.5 min readPublic vs Private IP Address: What's the Difference?Your router has a public IP and your devices have private ones. Learn how they differ, the private ranges, and why it matters.5 min readHow to Change Your IP Address: 5 Methods That WorkNeed a new IP address? Here are five practical ways to change it, from restarting your router to using a VPN, and what each one really does.6 min readCan Someone Track You by Your IP Address?An IP address reveals your approximate location and ISP, not your home address. Here is what others can and cannot learn from it.5 min readWhy Does My IP Address Keep Changing?Most home connections use dynamic IP addresses. Learn why yours changes, how DHCP leases and CGNAT work, and when to ask for a static IP.5 min readDNS Records Explained: A, AAAA, MX, TXT, CNAME and MoreA practical guide to the DNS record types you will meet most often, what each one does, and how to check them for any domain.7 min readWebRTC Leaks: How Your Real IP Can Escape a VPNWebRTC can reveal your real IP address even behind a VPN. Learn how the leak happens, how to test for it, and how to stop it.6 min readWhat Is Port Forwarding and How Do You Test It?Port forwarding lets outside devices reach a service on your home network. Learn how it works, how to set it up, and how to check a port is open.6 min readCIDR and Subnet Masks Explained: How to Calculate ThemUnderstand CIDR notation and subnet masks, and learn how to calculate network ranges and host counts with worked examples.6 min readHow to Fix Slow DNS Lookup: 8 Fixes That WorkA slow DNS lookup makes every website feel sluggish. Learn how to measure it and fix it by changing resolvers, flushing caches and more.7 min readHow to Check If a Port Is Open on Windows, Mac, Linux and OnlineFour reliable ways to check whether a port is open, from built-in commands on your own computer to an online test from the internet.6 min readHow to Change Your IP Address on Windows 11Step-by-step ways to change the IP address on a Windows 11 PC: set a static address, renew a DHCP lease, or get a new public IP.5 min readHow to Find a Printer's IP Address (Windows, Mac and Router)Need your printer's IP address? Five quick ways to find it, from the printer's own screen to your router's device list.4 min readIs Your IP Address Blacklisted? How to Check and Fix ItBlocklists can stop your email and trigger captchas. Learn how to check whether your IP is listed, why it happens and how to get removed.6 min readHow to Find Your Router's IP Address (Windows, Mac, Phone)Find your router's IP address on Windows, Mac, iPhone, Android and Linux, plus the common defaults and how to log in safely.5 min readWhat Is My ISP? How to Find Your Internet ProviderFind out who your internet service provider is in seconds, why the name can differ from the brand, and what an ISP can see.4 min readIs My VPN Working? How to Test It in 5 MinutesSix quick tests to check that your VPN is really working: IP, IPv6, WebRTC, DNS, time zone and kill switch.6 min readWhat Is Ping? How to Test It and Lower ItPing is the delay between your device and a server. Learn what a good ping is, how to test it and how to lower it.5 min read
Free tools
IP LookupLocation, ISP and ASN of any IP or domainDNS LookupA, AAAA, MX, TXT, NS, CNAME, SOA and CAA recordsReverse DNSFind the hostname behind any IP addressIP ReputationVPN, proxy, Tor and blocklist checkWHOISDomain and IP registration detailsHTTP HeadersThe headers your browser sends to websitesBrowser InfoUser agent, screen, language and morePort CheckerCheck if a port is open on your IPSpeed TestLatency, download and upload speedPing TestCheck your latency and jitterWebRTC Leak TestSee if your browser leaks your real IPSubnet CalculatorCIDR ranges, masks and host counts