Learn networking

Clear, practical guides to IP addresses, DNS, domains, ports and internet security, written for everyone from curious beginners to IT professionals.

IP Address Basics

IP Address Basics What Is an IP Address? A Plain-English Guide Learn what an IP address is, how it works, the difference between IPv4 and IPv6, and what your IP address reveals about you online. 7 min read

IP Address Basics IPv4 vs IPv6: What's the Difference? IPv4 vs IPv6 explained: address formats, why IPv4 ran out, NAT, how IPv6 improves routing and how to tell which one your connection uses. 8 min read

IP Address Basics Public vs Private IP Addresses Explained What is the difference between a public and a private IP address? Learn the private ranges, how NAT connects them and how to find each one. 6 min read

IP Address Basics Static vs Dynamic IP Address: Which Do You Need? Static vs dynamic IP addresses compared: how DHCP works, pros and cons of each, costs, and when a static IP is worth it for home or business. 6 min read

IP Address Basics How to Find Your IP Address on Any Device Step-by-step instructions to find your public and private IP address on Windows, macOS, Linux, iPhone, Android, Chromebook and your router. 8 min read

IP Address Basics Why Does My IP Address Change? Why your public and local IP addresses change: DHCP leases, router restarts, mobile networks, CGNAT and VPNs, and how to get an IP that stays the same. 6 min read

IP Address Basics How to Find Out Who Your Internet Provider Is Ways to identify your internet service provider from your IP address, router, bill or command line, and what your ISP can see about you. 5 min read

Privacy

Privacy How to Hide Your IP Address: 6 Methods Compared Compare the best ways to hide your IP address, including VPNs, Tor, proxies, iCloud Private Relay and mobile data, with pros, cons and limits. 8 min read

Privacy How to Change Your IP Address (Public and Local) Simple ways to change your public IP address and your local IP address on Windows, Mac, iPhone and Android, plus how to verify the change. 7 min read

Privacy How Accurate Is IP Geolocation? Why IP location is often wrong, how geolocation databases work, typical accuracy at country and city level, and how to correct your location. 6 min read

Privacy VPN vs Proxy: How They Change Your IP Address VPN vs proxy vs Tor compared: how each one changes your visible IP address, what they encrypt, typical use cases and the leaks to watch for. 7 min read

Privacy What Are DNS and WebRTC Leaks? How DNS and WebRTC leaks reveal your real IP address or browsing to your ISP while using a VPN, how to test for them, and how to fix them. 7 min read

Privacy What Is a Proxy Server? Types, Uses and Risks Forward and reverse proxies explained: HTTP, SOCKS5, transparent and residential proxies, how they change your IP, and the risks of free proxies. 7 min read

Troubleshooting

Troubleshooting How to Use Ping and Traceroute to Diagnose Network Problems Learn to run ping and traceroute on Windows, macOS and Linux, read latency, jitter and packet loss, and pinpoint where a connection breaks. 9 min read

Troubleshooting How to Fix Common Internet Connection Problems A practical checklist to fix no internet, slow speeds, Wi-Fi dropouts, DNS errors and 'connected, no internet' on Windows, Mac, phones and routers. 10 min read

Troubleshooting How to Troubleshoot IPv6 Connectivity Fix IPv6 problems step by step: check router and ISP support, prefix delegation, SLAAC vs DHCPv6, firewalls, VPN conflicts and test results. 8 min read

Troubleshooting How to Set Up Port Forwarding (Step by Step) Set up port forwarding on any router: reserve a local IP, create the rule, open the firewall and test it, plus fixes for CGNAT and double NAT. 9 min read

DNS & Domains

DNS & Domains What Is DNS and How Does It Work? DNS explained step by step: resolvers, root and TLD servers, caching, TTL, and why DNS changes take time to propagate around the world. 8 min read

DNS & Domains DNS Record Types Explained: A, AAAA, CNAME, MX, TXT and More A practical guide to DNS record types including A, AAAA, CNAME, MX, NS, TXT, SOA, CAA, SRV and PTR, with examples of when to use each. 9 min read

DNS & Domains What Is Reverse DNS (rDNS) and Why It Matters Reverse DNS explained: PTR records, in-addr.arpa, forward-confirmed reverse DNS, and why mail servers reject email without valid rDNS. 5 min read

DNS & Domains What Is WHOIS? Domain Lookup, RDAP and Privacy What WHOIS data shows, how RDAP is replacing it, why most owner details are redacted, and how to use WHOIS to research a domain or IP address. 6 min read

DNS & Domains What Is DNSSEC and How Does It Work? DNSSEC explained: signed zones, DNSKEY, RRSIG and DS records, the chain of trust from the root, validation failures and how to enable it. 8 min read

DNS & Domains DNS over HTTPS (DoH) and DNS over TLS Explained What encrypted DNS is, how DoH and DoT differ, privacy benefits and limits, and how to enable them in Windows, macOS, Android, iOS and browsers. 8 min read

DNS & Domains How to Find the IP Address of a Website Find any website's IP address with ping, nslookup, dig or an online lookup, and learn why CDNs, load balancers and IPv6 return different answers. 6 min read

Networking

Networking 192.168.1.1, 192.168.0.1 and 10.0.0.1: Router Login Guide How to log in to your router at 192.168.1.1, 192.168.0.1 or 10.0.0.1, find your default gateway, and fix the page when it will not load. 7 min read

Networking What Is Localhost (127.0.0.1)? Localhost and 127.0.0.1 explained: the loopback interface, ::1 in IPv6, how developers use it, and common errors like connection refused. 5 min read

Networking Subnet Masks and CIDR Notation Made Simple Understand subnet masks, CIDR notation like /24, network and broadcast addresses, and how to calculate usable hosts with worked examples. 9 min read

Networking Common Network Ports and What They Are Used For A reference to common TCP and UDP ports like 22, 80, 443, 3389 and 25565: what runs on them, security tips and how to check if a port is open. 8 min read

Networking What Is an ASN (Autonomous System Number)? Learn what an Autonomous System Number is, how BGP uses ASNs to route internet traffic, and how to find the ASN behind any IP address. 6 min read

Networking What Is CGNAT (Carrier-Grade NAT)? Carrier-grade NAT explained: how ISPs share one public IPv4 address between customers, how to tell if you are behind CGNAT, and how to work around it. 7 min read

Networking What Is NAT (Network Address Translation)? How NAT lets many devices share one public IP address, the difference between SNAT, DNAT and PAT, port forwarding, and why IPv6 does not need NAT. 7 min read

Networking What Is a MAC Address? Format, OUI and Privacy MAC addresses explained: the 48-bit format, OUI vendor prefixes, MAC vs IP address, randomized private Wi-Fi addresses and how to find yours. 7 min read

Networking HTTP Status Codes Explained: 200, 301, 404, 500 and More A complete guide to HTTP status codes, what 1xx to 5xx responses mean, which redirects to use for SEO, and how to fix common errors. 9 min read

Networking What Is DHCP and How Does It Assign IP Addresses? How DHCP automatically gives devices an IP address, gateway and DNS server: the DORA process, leases, reservations and fixes for DHCP errors. 7 min read

Networking TCP vs UDP: Differences, Ports and When Each Is Used TCP vs UDP explained: reliability, handshakes, speed, common ports and protocols, and why games, video calls and DNS prefer UDP. 7 min read

Networking What Does the IP Address 0.0.0.0 Mean? The meaning of 0.0.0.0 in different contexts: unspecified address, listening on all interfaces, the default route, DHCP and blocking hosts. 5 min read

Networking What Is a Default Gateway and How Do I Find Mine? What a default gateway does, how routing decides where packets go, and how to find your gateway IP on Windows, Mac, Linux, iPhone and Android. 6 min read

Security

Security What Is an SSL/TLS Certificate? SSL and TLS certificates explained: how HTTPS works, DV vs OV vs EV, certificate chains, expiry, and how to fix common certificate errors. 7 min read

Security SPF, DKIM and DMARC Explained How SPF, DKIM and DMARC protect your domain from email spoofing, with example records, a rollout plan, and fixes for common errors. 9 min read

Security IP Blacklisted? How to Check and Get Delisted Why IP addresses end up on spam blocklists like Spamhaus, SpamCop and Barracuda, how to find the cause, fix it, and request delisting. 8 min read

Security What Is a Firewall? Types and How They Protect You Firewalls explained: packet filtering, stateful inspection, NAT, host vs network firewalls, next-generation firewalls and essential home settings. 7 min read

Security How to See Who Is Connected to Your Wi-Fi Find every device on your Wi-Fi from the router, an app or the command line, identify unknown devices by MAC address, and kick off intruders. 7 min read

Security How to Spot a Phishing Email: 12 Red Flags The 12 warning signs of phishing emails, how to check the sender, links and attachments safely, how SPF, DKIM and DMARC help, and what to do if you clicked. 9 min read

Security Website Security Checklist: 20 Checks for Small Business Sites A practical website security checklist: HTTPS and certificates, security headers, software updates, logins, backups, DNS and email protection, with free checks. 10 min read

AI & Content

AI & Content How to Tell If Text Was Written by AI (and Why Detectors Get It Wrong) The writing patterns that give AI text away, how AI detectors actually work, how accurate they are, and how to check a document fairly without false accusations. 9 min read

AI & Content What Are AI Hallucinations? How to Fact-Check ChatGPT Answers Why ChatGPT, Gemini and Claude invent facts, fake citations and broken links, and a step-by-step method to verify any AI answer before you rely on it. 8 min read

AI & Content How to Spot AI-Generated Images: Metadata, C2PA and Visual Clues Check whether a photo is AI-generated: Content Credentials (C2PA), IPTC AI labels, EXIF data, error level analysis, reverse image search and the visual tells. 8 min read

AI & Content What Counts as Plagiarism? Paraphrasing, Citations and How to Check Your Work Plain-English guide to plagiarism: copying vs paraphrasing vs patchwriting, self-plagiarism, AI-written text, how to cite properly and how to check a text. 8 min read

Websites & SEO

Websites & SEO What Is GEO? How to Get Your Website Cited by ChatGPT and AI Overviews Generative engine optimization explained: how AI search engines choose sources, robots.txt and llms.txt for AI crawlers, structure, facts and trust signals. 9 min read

Files & Documents

Files & Documents ZIP vs RAR vs 7Z vs TAR.GZ: Which Archive Format Should You Use? Compare ZIP, RAR, 7Z and TAR.GZ for compression, compatibility, encryption and Unicode names, and learn which archive format to choose and how to convert. 8 min read

Files & Documents How to Password Protect a PDF, Word, Excel or ZIP File (and Remove It) How file encryption works for PDF, Word, Excel, PowerPoint and ZIP, how strong it really is, how to add or remove a password, and mistakes to avoid. 8 min read

Files & Documents How to Reduce PDF File Size Without Losing Quality Why PDFs get big and how to shrink them: image resolution, fonts, scanned pages, lossless vs image compression, and the right settings for email and uploads. 7 min read

Developers

Developers How Online Compilers Work: Running C, Python and R in Your Browser with WebAssembly How WebAssembly lets C, C++, Python, R and SQL run inside a browser tab, how it compares with server-based online compilers, and its limits. 8 min read

Developers What Is JSON? Syntax, Common Errors and How to Validate It JSON explained with examples: objects, arrays, data types, the most common syntax errors and how to fix them, JSON vs YAML vs XML, and how to validate JSON. 7 min read

Router login guides

Router login192.168.1.1

Router login192.168.0.1

Router login10.0.0.1

Router login192.168.1.254

Router login192.168.100.1

Router login192.168.8.1