{"id":1546,"date":"2025-06-25T18:10:40","date_gmt":"2025-06-25T17:10:40","guid":{"rendered":"https:\/\/workboot.fr\/ciela\/?page_id=1546"},"modified":"2025-06-25T18:26:58","modified_gmt":"2025-06-25T17:26:58","slug":"les-classes-ipv4","status":"publish","type":"page","link":"https:\/\/workboot.fr\/ciela\/les-classes-ipv4\/","title":{"rendered":"Les Classes (IPV4)"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">En r\u00e9seau, quand on parle de <strong>classes<\/strong>, on fait r\u00e9f\u00e9rence \u00e0 un ancien syst\u00e8me de <strong>classement des adresses IPv4<\/strong> en plusieurs <strong>cat\u00e9gories<\/strong> (classes A, B, C, D, E). C\u2019\u00e9tait utilis\u00e9 au d\u00e9but d\u2019Internet pour simplifier l\u2019attribution des adresses IP, mais cela reste <strong>important pour comprendre le fonctionnement des adresses IP et du subnetting<\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83e\uddee Une adresse IPv4, c\u2019est quoi ?<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Format : <code>X.X.X.X<\/code> (ex : <code>192.168.1.1<\/code>)<\/li>\n\n\n\n<li>32 bits \u2192 divis\u00e9e en <strong>4 octets<\/strong> (8 bits chacun)<\/li>\n\n\n\n<li>Il y a <strong>2 parties<\/strong> :\n<ul class=\"wp-block-list\">\n<li><strong>Identifiant r\u00e9seau<\/strong> (<em>Network ID<\/em>)<\/li>\n\n\n\n<li><strong>Identifiant h\u00f4te<\/strong> (<em>Host ID<\/em>)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83d\udce6 Les classes d\u2019adresses IPv4 (A, B, C)<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Classe<\/th><th>Octet de d\u00e9but (1er)<\/th><th>Plage d\u2019adresses<\/th><th>Bits r\u00e9seau<\/th><th>Bits h\u00f4tes<\/th><th>Nombre d\u2019h\u00f4tes<\/th><th>Exemple<\/th><\/tr><\/thead><tbody><tr><td>A<\/td><td>1 \u00e0 126<\/td><td><code>1.0.0.0<\/code> \u00e0 <code>126.255.255.255<\/code><\/td><td>8<\/td><td>24<\/td><td>~16 millions<\/td><td><code>10.0.0.1<\/code><\/td><\/tr><tr><td>B<\/td><td>128 \u00e0 191<\/td><td><code>128.0.0.0<\/code> \u00e0 <code>191.255.255.255<\/code><\/td><td>16<\/td><td>16<\/td><td>~65 000<\/td><td><code>172.16.0.1<\/code><\/td><\/tr><tr><td>C<\/td><td>192 \u00e0 223<\/td><td><code>192.0.0.0<\/code> \u00e0 <code>223.255.255.255<\/code><\/td><td>24<\/td><td>8<\/td><td>254<\/td><td><code>192.168.1.1<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83d\udce1 Et les autres classes ?<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Classe<\/th><th>Usage<\/th><th>Plage d\u2019adresses<\/th><\/tr><\/thead><tbody><tr><td>D<\/td><td>Multidiffusion (multicast)<\/td><td><code>224.0.0.0<\/code> \u00e0 <code>239.255.255.255<\/code><\/td><\/tr><tr><td>E<\/td><td>R\u00e9serv\u00e9e (exp\u00e9rimental)<\/td><td><code>240.0.0.0<\/code> \u00e0 <code>255.255.255.255<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83d\udd10 Adresses <strong>priv\u00e9es<\/strong> par classe (non rout\u00e9es sur Internet)<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Classe<\/th><th>Plage priv\u00e9e<\/th><th>Usage typique<\/th><\/tr><\/thead><tbody><tr><td>A<\/td><td><code>10.0.0.0<\/code> \u00e0 <code>10.255.255.255<\/code><\/td><td>R\u00e9seaux internes tr\u00e8s grands<\/td><\/tr><tr><td>B<\/td><td><code>172.16.0.0<\/code> \u00e0 <code>172.31.255.255<\/code><\/td><td>R\u00e9seaux d\u2019entreprise<\/td><\/tr><tr><td>C<\/td><td><code>192.168.0.0<\/code> \u00e0 <code>192.168.255.255<\/code><\/td><td>R\u00e9seaux domestiques (Wi-Fi, box)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83c\udfaf Exemple concret :<\/h2>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">Si ton PC a une IP comme <code>192.168.1.10<\/code>, c\u2019est :<\/p>\n<\/blockquote>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Une <strong>adresse priv\u00e9e<\/strong><\/li>\n\n\n\n<li>De <strong>classe C<\/strong><\/li>\n\n\n\n<li>Utilis\u00e9e sur un r\u00e9seau local (LAN)<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83e\udde0 \u00c0 retenir :<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Le syst\u00e8me par classes est <strong>d\u00e9suet<\/strong> (remplac\u00e9 par <strong>le CIDR \/ le subnetting<\/strong>), mais reste utile pour :\n<ul class=\"wp-block-list\">\n<li>comprendre comment l\u2019adressage fonctionne<\/li>\n\n\n\n<li>bien d\u00e9marrer avec les notions de r\u00e9seau<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>Aujourd\u2019hui, on utilise des <strong>masques de sous-r\u00e9seau (\/24, \/16&#8230;)<\/strong> plus flexibles<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/workboot.fr\/ciela\/les-classes\/\" data-type=\"page\" data-id=\"1549\">TD : sur les classes IPV4<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>En r\u00e9seau, quand on parle de classes, on fait r\u00e9f\u00e9rence \u00e0 un ancien syst\u00e8me de classement des adresses IPv4 en plusieurs cat\u00e9gories (classes A, B, C, D, E). C\u2019\u00e9tait utilis\u00e9 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_crdt_document":"","_uag_custom_page_level_css":"","footnotes":""},"class_list":["post-1546","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.3 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Les Classes (IPV4) - workboot<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/workboot.fr\/ciela\/les-classes-ipv4\/\" \/>\n<meta property=\"og:locale\" content=\"fr_FR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Les Classes (IPV4) - workboot\" \/>\n<meta property=\"og:description\" content=\"En r\u00e9seau, quand on parle de classes, on fait r\u00e9f\u00e9rence \u00e0 un ancien syst\u00e8me de classement des adresses IPv4 en plusieurs cat\u00e9gories (classes A, B, C, D, E). 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