Apprendre les réseaux

Des guides clairs et pratiques sur les adresses IP, le DNS, les domaines, les ports et la sécurité sur internet, pour tous, des débutants curieux aux professionnels de l'informatique.

Bases de l'adresse IP

Bases de l'adresse IP 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 de lecture
Bases de l'adresse IP 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 de lecture
Bases de l'adresse IP 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 de lecture
Bases de l'adresse IP 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 de lecture
Bases de l'adresse IP 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 de lecture
Bases de l'adresse IP 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 de lecture
Bases de l'adresse IP 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 de lecture

Confidentialité

Confidentialité 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 de lecture
Confidentialité 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 de lecture
Confidentialité 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 de lecture
Confidentialité 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 de lecture
Confidentialité 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 de lecture
Confidentialité 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 de lecture

Dépannage

Dépannage 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 de lecture
Dépannage 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 de lecture
Dépannage 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 de lecture
Dépannage 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 de lecture

DNS et domaines

DNS et domaines 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 de lecture
DNS et domaines 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 de lecture
DNS et domaines 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 de lecture
DNS et domaines 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 de lecture
DNS et domaines 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 de lecture
DNS et domaines 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 de lecture
DNS et domaines 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 de lecture

Réseaux

Réseaux What Is a Router IP Address? Default Gateway Explained What a router IP address (default gateway) is, why it is usually 192.168.1.1, 192.168.0.1 or 10.0.0.1, how to find yours, and how it differs from your public IP. 7 min de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture
Réseaux 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 de lecture

Sécurité

Sécurité 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 de lecture
Sécurité 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 de lecture
Sécurité 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 de lecture
Sécurité 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 de lecture
Sécurité 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 de lecture
Sécurité 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 de lecture
Sécurité 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 de lecture

IA et contenu

IA et contenu How to Tell If Text Was Written by AI (and Why Detectors Fail) 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 de lecture
IA et contenu 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 de lecture
IA et contenu 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 de lecture
IA et contenu What Counts as Plagiarism? Paraphrasing and Citations 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 de lecture

Sites web et SEO

Sites web et SEO What Is GEO? How to Get 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 de lecture

Fichiers et documents

Fichiers et 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 de lecture
Fichiers et documents How to Password Protect PDF, Word, Excel and ZIP Files 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 de lecture
Fichiers et 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 de lecture

Développeurs

Développeurs How Online Compilers Work: Running Code in Your Browser 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 de lecture
Développeurs 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 de lecture

Santé

Santé How to Test Your Eyesight at Home (and What 20/20 Means) How to check your vision at home with an eye chart, what 20/20 and 6/6 mean, myopia, hyperopia and astigmatism explained, and when to see an optometrist. 9 min de lecture
Santé Types of Colour Blindness: Protan, Deutan and Tritan Colour blindness types explained: protan, deutan and tritan, which colours get confused, how colour vision is tested, and practical tips for daily life. 9 min de lecture
Santé How to Check Your Hearing at Home: Online Tests Explained How online hearing tests work, how to take one with headphones, how to read an audiogram, what a hearing score means and when to see an audiologist. 9 min de lecture
Santé What Is BMI? What Your Body Mass Index Means (and Its Limits) What BMI is, how to calculate it, what the adult categories mean, why some groups use lower cut-offs, how children differ, and what BMI cannot tell you. 10 min de lecture

Appareils

Appareils Microphone Not Working? Fixes for Windows, Mac and Phone Microphone not working? Step-by-step fixes for Windows, Mac, Android, iPhone and browser permissions, plus the right settings in Zoom, Teams and Discord. 9 min de lecture
Appareils What Is a Good Typing Speed? WPM Explained What counts as a good typing speed: how words per minute is calculated, typical WPM ranges, speeds asked for in jobs, and a plan to type faster. 9 min de lecture

Sommeil

Sommeil White, Pink and Brown Noise: What's the Difference? White, pink, brown and green noise explained: how each one sounds, what the colours mean in acoustics, and which noise to choose for sleep or focus. 8 min de lecture
Sommeil Is White Noise Safe for Babies? Volume, Distance and Timing Is white noise safe for babies? How loud it should be, how far from the cot, how long to play it, and what research says about infant sleep machines. 8 min de lecture

Quotidien

Quotidien Metric to Imperial: cm to Inches, kg to Pounds and °C to °F Convert cm to inches, kg to pounds and stones, and Celsius to Fahrenheit: exact formulas, quick mental shortcuts, worked examples and handy tables. 9 min de lecture
Quotidien How to Read Roman Numerals (Chart and Rules) How Roman numerals work: the seven symbols, the adding and subtractive rules, how to read and write years, a 1 to 100 chart and why IIII appears on clocks. 9 min de lecture
Quotidien How Is GPA Calculated? Weighted vs Unweighted GPA How to calculate GPA on the US 4.0 scale step by step: grade points, credits, semester and cumulative GPA, and how weighted GPA for honors and AP works. 9 min de lecture
Quotidien Barcode Types Explained: EAN vs UPC vs Code 128 Common barcode types compared: EAN-13 and UPC-A for retail, Code 128 and Code 39 for labels, ITF-14 for cartons, plus check digits and when you need GS1. 8 min de lecture
Quotidien How to Tune a Guitar by Ear and with a Tuner Tune a guitar with a tuner or by ear: string notes and frequencies, the 5th-fret method, harmonics, alternate tunings and how to keep a guitar in tune. 8 min de lecture
Quotidien Morse Code Alphabet and How to Learn It The full Morse code alphabet with numbers, punctuation and prosigns, the timing rules, and how to learn Morse by ear with the Koch and Farnsworth methods. 9 min de lecture

Argent

Argent How Exchange Rates Work (and Why Your Bank's Rate Differs) How exchange rates work: mid-market and reference rates, buy and sell spreads, cross rates, what moves a currency and how to avoid poor rates when you pay abroad. 10 min de lecture
Argent Compound Interest Explained (Formula and Examples) How compound interest works: the formula A = P(1 + r/n)^nt with worked examples, APY vs APR, regular deposits, the rule of 72, inflation, fees and debt. 9 min de lecture

Guides de connexion au routeur

Connexion au routeur192.168.1.1
Connexion au routeur192.168.0.1
Connexion au routeur10.0.0.1
Connexion au routeur192.168.1.254
Connexion au routeur192.168.100.1
Connexion au routeur192.168.8.1
Copié dans le presse-papiers