{"id":41842,"date":"2026-06-21T15:35:43","date_gmt":"2026-06-21T08:35:43","guid":{"rendered":"https:\/\/interdata.vn\/blog\/?p=41842"},"modified":"2026-06-21T15:37:29","modified_gmt":"2026-06-21T08:37:29","slug":"subnet-mask-la-gi","status":"publish","type":"post","link":"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/","title":{"rendered":"Subnet Mask L\u00e0 G\u00ec? C\u00e1ch T\u00ednh &#038; Chia M\u1ea1ng Con Nhanh"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-white ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">N\u1ed8I DUNG<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 eztoc-toggle-hide-by-default' ><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#BD-%E2%80%93-Starter\" >BD &#8211; Starter<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#Premium-Base\" >Premium Base<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#BD-%E2%80%93-Personal\" >BD &#8211; Personal<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#Cloud-Day-%E2%80%93-Base\" >Cloud-Day &#8211; Base<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#1-Subnet-Mask-La-Gi\" >1. Subnet Mask L\u00e0 G\u00ec?<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#Xay-dung-phan-vung-mang-an-toan-cho-du-an-cua-ban\" >X\u00e2y d\u1ef1ng ph\u00e2n v\u00f9ng m\u1ea1ng an to\u00e0n cho d\u1ef1 \u00e1n c\u1ee7a b\u1ea1n<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#2-Cac-Lop-Dia-Chi-IP-Va-Default-Subnet-Mask\" >2. C\u00e1c L\u1edbp \u0110\u1ecba Ch\u1ec9 IP V\u00e0 Default Subnet Mask<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#3-Cach-Tinh-Subnet-Mask-Chi-Tiet-Tu-Nhi-Phan-Sang-Thap-Phan\" >3. C\u00e1ch T\u00ednh Subnet Mask Chi Ti\u1ebft T\u1eeb Nh\u1ecb Ph\u00e2n Sang Th\u1eadp Ph\u00e2n<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#4-Quy-Tac-Tinh-Nhanh-Subnet-Mask-Phuong-Phap-Magic-Number\" >4. Quy T\u1eafc T\u00ednh Nhanh Subnet Mask (Ph\u01b0\u01a1ng Ph\u00e1p Magic Number)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#5-Ung-Dung-Thuc-Te-Cau-Hinh-Subnet-Mask-Tren-He-Dieu-Hanh-Docker\" >5. \u1ee8ng D\u1ee5ng Th\u1ef1c T\u1ebf: C\u1ea5u H\u00ecnh Subnet Mask Tr\u00ean H\u1ec7 \u0110i\u1ec1u H\u00e0nh &amp; Docker<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#A-Thiet-lap-mang-tinh-tren-Linux-Ubuntu-Server-dung-Netplan\" >A. Thi\u1ebft l\u1eadp m\u1ea1ng t\u0129nh tr\u00ean Linux (Ubuntu Server d\u00f9ng Netplan)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#B-Cau-hinh-nhanh-qua-giao-dien-dong-lenh-Windows-Server\" >B. C\u1ea5u h\u00ecnh nhanh qua giao di\u1ec7n d\u00f2ng l\u1ec7nh Windows Server<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#C-Phan-vung-mang-doc-lap-trong-moi-truong-Docker-Container\" >C. Ph\u00e2n v\u00f9ng m\u1ea1ng \u0111\u1ed9c l\u1eadp trong m\u00f4i tr\u01b0\u1eddng Docker Container<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#6-Cac-Loi-Thuong-Gap-Khi-Chia-Mang-Con-Va-Cach-Khac-Phuc\" >6. C\u00e1c L\u1ed7i Th\u01b0\u1eddng G\u1eb7p Khi Chia M\u1ea1ng Con V\u00e0 C\u00e1ch Kh\u1eafc Ph\u1ee5c<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#Linh-hoat-mo-rong-tai-nguyen-mang-tren-dam-may\" >Linh ho\u1ea1t m\u1edf r\u1ed9ng t\u00e0i nguy\u00ean m\u1ea1ng tr\u00ean \u0111\u00e1m m\u00e2y<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#7-Cau-Hoi-Thuong-Gap-FAQs-Ve-Mang-Con\" >7. C\u00e2u H\u1ecfi Th\u01b0\u1eddng G\u1eb7p (FAQs) V\u1ec1 M\u1ea1ng Con<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#Tong-Ket-Kien-Thuc-Ve-Mat-Na-Mang\" >T\u1ed5ng K\u1ebft Ki\u1ebfn Th\u1ee9c V\u1ec1 M\u1eb7t N\u1ea1 M\u1ea1ng<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#BD-%E2%80%93-Starter-2\" >BD &#8211; Starter<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#Premium-Base-2\" >Premium Base<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#BD-%E2%80%93-Personal-2\" >BD &#8211; Personal<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"https:\/\/interdata.vn\/blog\/subnet-mask-la-gi\/#Cloud-Day-%E2%80%93-Base-2\" >Cloud-Day &#8211; Base<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n\n\n<style>\n.interdata-plan-carousel{--blue:#005bea;--blue-dark:#004dcc;--text:#071832;--border:#d8e6fb;--bg:#f3f8ff;container-type:inline-size;background:var(--bg);padding:14px 12px;overflow:hidden}\n.interdata-carousel-heading{color:#003fbd;font-size:18px;line-height:1.35;font-weight:800;text-align:center;margin:0 0 14px}\n.interdata-plan-track{display:flex;gap:12px;overflow-x:auto;scroll-snap-type:x mandatory;padding:0 0 8px;-webkit-overflow-scrolling:touch;scrollbar-width:none}\n.interdata-plan-track::-webkit-scrollbar{display:none}\n.interdata-plan-card,.interdata-plan-card *{box-sizing:border-box}\n.interdata-plan-card{flex:0 0 calc(25% - 9px);min-width:205px;background:#fff;border:1px solid var(--border);border-radius:8px;padding:18px 14px 14px;min-height:382px;display:flex;flex-direction:column;scroll-snap-align:start;box-shadow:0 5px 14px rgba(0,62,145,.08)}\n.interdata-plan-title{color:var(--blue-dark);font-size:17px;line-height:1.25;font-weight:800;text-align:center;margin:0 0 8px}\n.interdata-plan-price{color:var(--blue-dark);font-size:32px;line-height:1;font-weight:900;text-align:center;margin-bottom:14px;white-space:nowrap;letter-spacing:0}\n.interdata-plan-price span{font-size:12px;font-weight:800;margin-left:2px}\n.interdata-plan-badge{align-self:center;display:inline-flex;align-items:center;justify-content:center;background:#ff3934;color:#fff;border-radius:5px;padding:8px 10px;font-size:10px;line-height:1;font-weight:800;margin-bottom:18px;white-space:nowrap}\n.interdata-plan-features{list-style:none!important;padding:0!important;margin:0!important}\n.interdata-plan-features li{display:flex;gap:8px;align-items:flex-start;color:var(--text);font-size:13px;line-height:1.35;font-weight:700;text-align:left;margin:0 0 11px!important;padding:0!important}\n.interdata-plan-icon{width:15px;min-width:15px;height:15px;color:#0069ff;margin-top:2px}\n.interdata-plan-icon svg{display:block;width:100%;height:100%;fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}\n.interdata-plan-spacer{flex:1}\n.interdata-plan-button{display:flex;align-items:center;justify-content:center;min-height:44px;width:100%;background:var(--blue);color:#fff!important;border-radius:5px;font-size:14px;font-weight:800;text-decoration:none!important;box-shadow:0 7px 14px rgba(0,91,234,.24);transition:transform .2s ease,background .2s ease}\n.interdata-plan-button:hover{background:var(--blue-dark);color:#fff!important;transform:translateY(-1px)}\n@container (max-width:860px){.interdata-plan-card{flex-basis:calc(33.333% - 8px);min-width:205px}}\n@container (max-width:640px){.interdata-plan-card{flex-basis:calc(50% - 7px);min-width:215px}}\n@container (max-width:480px){.interdata-plan-carousel{padding:12px 10px}.interdata-carousel-heading{font-size:16px}.interdata-plan-card{flex-basis:86%;min-width:235px}.interdata-plan-price{font-size:31px}}\n@media (max-width:360px){.interdata-plan-card{flex-basis:90%;min-width:220px}.interdata-plan-price{font-size:29px}.interdata-plan-badge{font-size:9px}}\n<\/style>\n\n<div class=\"interdata-plan-carousel\">\n  <div class=\"interdata-carousel-heading\"><span style=\"font-family: Roboto, sans-serif; color: red;\">Si\u00eau \u01afu \u0110\u00e3i VPS \/ CLOUD SERVER - Ti\u1ebft Ki\u1ec7m \u0110\u1ebfn 70%<\/span><\/div>\n\n  <svg width=\"0\" height=\"0\" style=\"position:absolute;visibility:hidden\" aria-hidden=\"true\">\n    <symbol id=\"id-icon-cpu\" viewBox=\"0 0 24 24\"><rect x=\"7\" y=\"7\" width=\"10\" height=\"10\" rx=\"2\"><\/rect><path d=\"M4 9h3M4 15h3M17 9h3M17 15h3M9 4v3M15 4v3M9 17v3M15 17v3\"><\/path><path d=\"M10 10h4v4h-4z\"><\/path><\/symbol>\n    <symbol id=\"id-icon-ram\" viewBox=\"0 0 24 24\"><rect x=\"4\" y=\"8\" width=\"16\" height=\"8\" rx=\"2\"><\/rect><path d=\"M7 16v2M11 16v2M15 16v2M19 16v2M7 11h1M11 11h1M15 11h1\"><\/path><\/symbol>\n    <symbol id=\"id-icon-storage\" viewBox=\"0 0 24 24\"><rect x=\"6\" y=\"3\" width=\"12\" height=\"18\" rx=\"2\"><\/rect><path d=\"M9 7h6\"><\/path><circle cx=\"12\" cy=\"16\" r=\"1.5\"><\/circle><\/symbol>\n    <symbol id=\"id-icon-network\" viewBox=\"0 0 24 24\"><path d=\"M5 12.5a10 10 0 0 1 14 0\"><\/path><path d=\"M8.5 16a5 5 0 0 1 7 0\"><\/path><path d=\"M12 19h.01\"><\/path><\/symbol>\n    <symbol id=\"id-icon-gift\" viewBox=\"0 0 24 24\"><rect x=\"3\" y=\"8\" width=\"18\" height=\"13\" rx=\"2\"><\/rect><path d=\"M12 8v13M3 12h18\"><\/path><path d=\"M7.5 8C6.1 8 5 6.9 5 5.5S6.1 3 7.5 3C10 3 12 8 12 8\"><\/path><path d=\"M16.5 8C17.9 8 19 6.9 19 5.5S17.9 3 16.5 3C14 3 12 8 12 8\"><\/path><\/symbol>\n  <\/svg>\n\n  <div class=\"interdata-plan-track\">\n    <article class=\"interdata-plan-card\">\n      <h3 class=\"interdata-plan-title\">BD - Starter<\/h3>\n      <div class=\"interdata-plan-price\">699K<span>\/n\u0103m<\/span><\/div>\n      <div class=\"interdata-plan-badge\">GIA H\u1ea0N KH\u00d4NG \u0110\u1ed4I GI\u00c1<\/div>\n      <ul class=\"interdata-plan-features\">\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-cpu\"><\/use><\/svg><\/span>1 vCPU Intel Xeon<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-ram\"><\/use><\/svg><\/span>2 GB RAM<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-storage\"><\/use><\/svg><\/span>20 GB NVMe U.2<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-network\"><\/use><\/svg><\/span>Network: 100 Mbps<\/li>\n      <\/ul>\n      <div class=\"interdata-plan-spacer\"><\/div>\n      <a class=\"interdata-plan-button\" href=\"https:\/\/support.interdata.vn\/index.php?rp=\/store\/interdata-day-2026\/bd-starter\" target=\"_blank\" rel=\"nofollow sponsored noopener\">\u0110\u0103ng k\u00fd ngay<\/a>\n    <\/article>\n\n    <article class=\"interdata-plan-card\">\n      <h3 class=\"interdata-plan-title\"><span class=\"ez-toc-section\" id=\"Premium-Base\"><\/span>Premium Base<span class=\"ez-toc-section-end\"><\/span><\/h3>\n      <div class=\"interdata-plan-price\">999K<span>\/n\u0103m<\/span><\/div>\n      <div class=\"interdata-plan-badge\">GIA H\u1ea0N KH\u00d4NG \u0110\u1ed4I GI\u00c1<\/div>\n      <ul class=\"interdata-plan-features\">\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-cpu\"><\/use><\/svg><\/span>3 vCore Intel Xeon<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-ram\"><\/use><\/svg><\/span>3 GB RAM<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-storage\"><\/use><\/svg><\/span>30 GB SSD NVMe U.2<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-network\"><\/use><\/svg><\/span>Network: 300 Mbps<\/li>\n      <\/ul>\n      <div class=\"interdata-plan-spacer\"><\/div>\n      <a class=\"interdata-plan-button\" href=\"https:\/\/support.interdata.vn\/index.php?rp=\/store\/cyber-week-2026\/premium-base\" target=\"_blank\" rel=\"nofollow sponsored noopener\">\u0110\u0103ng k\u00fd ngay<\/a>\n    <\/article>\n\n    <article class=\"interdata-plan-card\">\n      <h3 class=\"interdata-plan-title\">BD - Personal<\/h3>\n      <div class=\"interdata-plan-price\">1.456K<span>\/n\u0103m<\/span><\/div>\n      <div class=\"interdata-plan-badge\">GIA H\u1ea0N KH\u00d4NG \u0110\u1ed4I GI\u00c1<\/div>\n      <ul class=\"interdata-plan-features\">\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-cpu\"><\/use><\/svg><\/span>2 vCPU AMD 7H12<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-ram\"><\/use><\/svg><\/span>4 GB RAM<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-storage\"><\/use><\/svg><\/span>40 GB SSD NVMe U.2<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-network\"><\/use><\/svg><\/span>Network: 300 Mbps<\/li>\n      <\/ul>\n      <div class=\"interdata-plan-spacer\"><\/div>\n      <a class=\"interdata-plan-button\" href=\"https:\/\/support.interdata.vn\/index.php?rp=\/store\/interdata-day-2026\/bd-personal\" target=\"_blank\" rel=\"nofollow sponsored noopener\">\u0110\u0103ng k\u00fd ngay<\/a>\n    <\/article>\n\n    <article class=\"interdata-plan-card\">\n      <h3 class=\"interdata-plan-title\">Cloud-Day - Base<\/h3>\n      <div class=\"interdata-plan-price\">2.666K<span>\/n\u0103m<\/span><\/div>\n      <div class=\"interdata-plan-badge\">GIA H\u1ea0N KH\u00d4NG \u0110\u1ed4I GI\u00c1<\/div>\n      <ul class=\"interdata-plan-features\">\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-gift\"><\/use><\/svg><\/span>T\u1eb7ng 80 GB S3 v\u00e0 1 N\u0102M S\u1eec D\u1ee4NG khi mua 2 n\u0103m tr\u1edf l\u00ean<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-cpu\"><\/use><\/svg><\/span>4 vCPU AMD EPYC<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-ram\"><\/use><\/svg><\/span>6 GB RAM<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-storage\"><\/use><\/svg><\/span>60 GB SSD NVMe U.2<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-network\"><\/use><\/svg><\/span>Network: 10 Gbps<\/li>\n      <\/ul>\n      <div class=\"interdata-plan-spacer\"><\/div>\n      <a class=\"interdata-plan-button\" href=\"https:\/\/support.interdata.vn\/index.php?rp=\/store\/cloud-day-by-interdata-2026\/cloud-day-base\" target=\"_blank\" rel=\"nofollow sponsored noopener\">\u0110\u0103ng k\u00fd ngay<\/a>\n    <\/article>\n  <\/div>\n<\/div>\n\n\t<div id=\"gap-1327201698\" class=\"gap-element clearfix\" style=\"display:block; height:auto;\">\n\t\t\n<style>\n#gap-1327201698 {\n  padding-top: 30px;\n}\n<\/style>\n\t<\/div>\n\t\n<p style=\"text-align: justify;\"><span style=\"font-size: 100%;\">C\u1ea5u h\u00ecnh sai \u0111\u1ecba ch\u1ec9 m\u1ea1ng khi\u1ebfn c\u00e1c m\u00e1y ch\u1ee7 n\u1ed9i b\u1ed9 m\u1ea5t k\u1ebft n\u1ed1i ho\u1eb7c v\u00f4 t\u00ecnh l\u00e0m l\u1ed9 c\u01a1 s\u1edf d\u1eef li\u1ec7u quan tr\u1ecdng ra m\u00f4i tr\u01b0\u1eddng internet c\u00f4ng c\u1ed9ng l\u00e0 l\u1ed7i b\u1ea3o m\u1eadt kinh \u0111i\u1ec3n c\u1ee7a nhi\u1ec1u qu\u1ea3n tr\u1ecb vi\u00ean. Vi\u1ec7c hi\u1ec3u r\u00f5 b\u1ea3n ch\u1ea5t c\u1ee7a <strong>subnet mask<\/strong> gi\u00fap b\u1ea1n ph\u00e2n ranh gi\u1edbi ph\u00e2n m\u1ea3nh m\u1ea1ng h\u1ee3p l\u00fd, ng\u0103n ch\u1eb7n r\u1ee7i ro xung \u0111\u1ed9t IP v\u00e0 t\u1ed1i \u01b0u h\u00f3a lu\u1ed3ng d\u1eef li\u1ec7u truy\u1ec1n t\u1ea3i. \u0110\u1ec3 tri\u1ec3n khai m\u1ed9t ki\u1ebfn tr\u00fac m\u1ea1ng \u1ea3o h\u00f3a an to\u00e0n, k\u1ebft h\u1ee3p h\u1ea1 t\u1ea7ng m\u00e1y ch\u1ee7 hi\u1ec7u n\u0103ng cao c\u1ee7a <a style=\"background: linear-gradient(90deg, #1E3A8A 0%, #2563EB 100%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; text-decoration: none; font-weight: bold;\" href=\"\/\">InterData<\/a> s\u1ebd gi\u00fap h\u1ec7 th\u1ed1ng c\u1ee7a b\u1ea1n v\u1eadn h\u00e0nh \u1ed5n \u0111\u1ecbnh m\u00e0 kh\u00f4ng lo ng\u1ea1i c\u00e1c s\u1ef1 c\u1ed1 ngh\u1ebdn m\u1ea1ng v\u1eadt l\u00fd hay b\u1ea3o m\u1eadt c\u1ee5c b\u1ed9.<\/span><\/p>\n<div style=\"background-color: #eff6ff; padding: 20px; border: 1.5px solid #BFDBFE; border-radius: 12px; margin-bottom: 40px; box-shadow: 0 8px 20px rgba(37, 99, 235, 0.05);\">\n<p style=\"font-family: 'Be Vietnam Pro', sans-serif; font-weight: bold; font-size: 18px; margin-top: 0; margin-bottom: 15px; color: #1e3a8a;\">N\u1ed8I DUNG B\u00c0I VI\u1ebeT<\/p>\n<ul style=\"list-style-type: none; padding-left: 0; margin: 0;\">\n<li style=\"margin-bottom: 10px;\"><a style=\"text-decoration: none; color: #2563eb; font-weight: 600;\" href=\"#section1\">1. Subnet Mask L\u00e0 G\u00ec?<\/a><\/li>\n<li style=\"margin-bottom: 10px;\"><a style=\"text-decoration: none; color: #2563eb; font-weight: 600;\" href=\"#section2\">2. C\u00e1c L\u1edbp \u0110\u1ecba Ch\u1ec9 IP V\u00e0 Default Subnet Mask<\/a><\/li>\n<li style=\"margin-bottom: 10px;\"><a style=\"text-decoration: none; color: #2563eb; font-weight: 600;\" href=\"#section3\">3. C\u00e1ch T\u00ednh Subnet Mask Chi Ti\u1ebft T\u1eeb Nh\u1ecb Ph\u00e2n Sang Th\u1eadp Ph\u00e2n<\/a><\/li>\n<li style=\"margin-bottom: 10px;\"><a style=\"text-decoration: none; color: #2563eb; font-weight: 600;\" href=\"#section4\">4. Quy T\u1eafc T\u00ednh Nhanh Subnet Mask (Ph\u01b0\u01a1ng Ph\u00e1p Magic Number)<\/a><\/li>\n<li style=\"margin-bottom: 10px;\"><a style=\"text-decoration: none; color: #2563eb; font-weight: 600;\" href=\"#section5\">5. \u1ee8ng D\u1ee5ng Th\u1ef1c T\u1ebf: C\u1ea5u H\u00ecnh Subnet Mask Tr\u00ean H\u1ec7 \u0110i\u1ec1u H\u00e0nh &amp; Docker<\/a><\/li>\n<li style=\"margin-bottom: 10px;\"><a style=\"text-decoration: none; color: #2563eb; font-weight: 600;\" href=\"#section6\">6. C\u00e1c L\u1ed7i Th\u01b0\u1eddng G\u1eb7p Khi Chia M\u1ea1ng Con V\u00e0 C\u00e1ch Kh\u1eafc Ph\u1ee5c<\/a><\/li>\n<li style=\"margin-bottom: 10px;\"><a style=\"text-decoration: none; color: #2563eb; font-weight: 600;\" href=\"#section7\">7. C\u00e2u H\u1ecfi Th\u01b0\u1eddng G\u1eb7p (FAQs) V\u1ec1 M\u1ea1ng Con<\/a><\/li>\n<\/ul>\n<\/div>\n<h2 id=\"section1\" style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 24px; font-weight: bold; text-align: left; border-left: 5px solid #2563EB; padding-left: 15px; margin-top: 40px; margin-bottom: 20px; line-height: 1.4;\"><span class=\"ez-toc-section\" id=\"1-Subnet-Mask-La-Gi\"><\/span>1. Subnet Mask L\u00e0 G\u00ec?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Subnet mask l\u00e0 m\u1ed9t d\u00e3y s\u1ed1 32 bit d\u00f9ng \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh ph\u1ea7n n\u00e0o trong \u0111\u1ecba ch\u1ec9 IP thu\u1ed9c v\u1ec1 \u0111\u1ecbnh danh m\u1ea1ng (Network ID) v\u00e0 ph\u1ea7n n\u00e0o thu\u1ed9c v\u1ec1 \u0111\u1ecbnh danh thi\u1ebft b\u1ecb (Host ID). Vi\u1ec7c ph\u00e2n chia n\u00e0y gi\u00fap c\u00e1c thi\u1ebft b\u1ecb \u0111\u1ecbnh tuy\u1ebfn trong h\u1ec7 th\u1ed1ng m\u1ea1ng bi\u1ebft \u0111\u01b0\u1ee3c g\u00f3i tin c\u1ea7n chuy\u1ec3n h\u01b0\u1edbng n\u1ed9i b\u1ed9 hay ph\u1ea3i g\u1eedi ra ngo\u00e0i Internet th\u00f4ng qua c\u1ed5ng k\u1ebft n\u1ed1i m\u1eb7c \u0111\u1ecbnh (Default Gateway).<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-41844\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2026\/06\/Subnet-Mask-La-Gi-Cach-Tinh-Chia-Mang-Con-Nhanh.jpg\" alt=\"Subnet Mask L\u00e0 G\u00ec, C\u00e1ch T\u00ednh &amp; Chia M\u1ea1ng Con Nhanh\" width=\"700\" height=\"467\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2026\/06\/Subnet-Mask-La-Gi-Cach-Tinh-Chia-Mang-Con-Nhanh.jpg 1000w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2026\/06\/Subnet-Mask-La-Gi-Cach-Tinh-Chia-Mang-Con-Nhanh-300x200.jpg 300w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2026\/06\/Subnet-Mask-La-Gi-Cach-Tinh-Chia-Mang-Con-Nhanh-768x512.jpg 768w\" sizes=\"auto, (max-width: 700px) 100vw, 700px\" \/><\/p>\n<p style=\"text-align: justify;\">\u0110\u1ec3 hi\u1ec3u \u0111\u01a1n gi\u1ea3n h\u01a1n, h\u00e3y t\u01b0\u1edfng t\u01b0\u1ee3ng m\u1ed9t \u0111\u1ecba ch\u1ec9 IP gi\u1ed1ng nh\u01b0 m\u1ed9t \u0111\u1ecba ch\u1ec9 nh\u00e0 \u0111\u1ea7y \u0111\u1ee7, bao g\u1ed3m t\u00ean \u0111\u01b0\u1eddng v\u00e0 s\u1ed1 nh\u00e0 c\u1ee5 th\u1ec3. Subnet mask \u0111\u00f3ng vai tr\u00f2 nh\u01b0 m\u1ed9t b\u1ed9 l\u1ecdc gi\u00fap b\u00f3c t\u00e1ch ph\u1ea7n t\u00ean \u0111\u01b0\u1eddng ra kh\u1ecfi s\u1ed1 nh\u00e0. N\u00f3 gi\u00fap c\u00e1c thi\u1ebft b\u1ecb switch, router ph\u00e2n bi\u1ec7t \u0111\u01b0\u1ee3c nh\u1eefng m\u00e1y ch\u1ee7 n\u00e0o \u0111ang n\u1eb1m chung m\u1ed9t ph\u00e2n khu m\u1ea1ng \u0111\u1ec3 c\u00f3 th\u1ec3 giao ti\u1ebfp tr\u1ef1c ti\u1ebfp v\u1edbi nhau m\u00e0 kh\u00f4ng c\u1ea7n \u0111i qua b\u1ed9 \u0111\u1ecbnh tuy\u1ebfn trung gian.<\/p>\n<p style=\"text-align: justify;\">M\u1ed9t \u0111\u1ecba ch\u1ec9 IPv4 bao g\u1ed3m 32 bit, \u0111\u01b0\u1ee3c chia th\u00e0nh 4 nh\u00f3m (g\u1ecdi l\u00e0 c\u00e1c octet), m\u1ed7i octet g\u1ed3m 8 bit v\u00e0 ng\u0103n c\u00e1ch nhau b\u1eb1ng d\u1ea5u ch\u1ea5m. Subnet mask c\u0169ng c\u00f3 c\u1ea5u tr\u00fac t\u01b0\u01a1ng t\u1ef1. Khi bi\u1ec3u di\u1ec5n d\u01b0\u1edbi d\u1ea1ng nh\u1ecb ph\u00e2n, subnet mask lu\u00f4n b\u1eaft \u0111\u1ea7u b\u1eb1ng m\u1ed9t chu\u1ed7i c\u00e1c bit 1 li\u00ean t\u1ee5c v\u00e0 k\u1ebft th\u00fac b\u1eb1ng m\u1ed9t chu\u1ed7i c\u00e1c bit 0 li\u00ean t\u1ee5c. C\u00e1c bit 1 \u0111\u1ea1i di\u1ec7n cho Network ID, c\u00f2n c\u00e1c bit 0 \u0111\u1ea1i di\u1ec7n cho Host ID.<\/p>\n<ul style=\"list-style-type: disc; padding-left: 20px; margin-bottom: 25px; color: #1f2937;\">\n<li style=\"margin-bottom: 10px;\"><strong>\u0110\u1ecbnh danh m\u1ea1ng (Network ID):<\/strong> \u0110\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1edfi c\u00e1c bit 1 trong subnet mask. C\u00e1c thi\u1ebft b\u1ecb n\u1eb1m trong c\u00f9ng m\u1ed9t m\u1ea1ng LAN b\u1eaft bu\u1ed9c ph\u1ea3i c\u00f3 c\u00f9ng gi\u00e1 tr\u1ecb Network ID \u0111\u1ec3 nh\u1eadn di\u1ec7n nhau.<\/li>\n<li style=\"margin-bottom: 10px;\"><strong>\u0110\u1ecbnh danh thi\u1ebft b\u1ecb (Host ID):<\/strong> \u0110\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1edfi c\u00e1c bit 0 trong subnet mask. \u0110\u00e2y l\u00e0 \u0111\u1ecba ch\u1ec9 duy nh\u1ea5t g\u00e1n cho t\u1eebng m\u00e1y ch\u1ee7, m\u00e1y tr\u1ea1m ho\u1eb7c thi\u1ebft b\u1ecb ngo\u1ea1i vi trong ph\u00e2n v\u00f9ng m\u1ea1ng \u0111\u00f3.<\/li>\n<\/ul>\n<div style=\"display: flex; flex-wrap: wrap; background-color: #fff; border: 1.5px solid #BFDBFE; box-shadow: 0 8px 20px rgba(37,99,235,0.08); border-radius: 12px; overflow: hidden; margin: 35px 0;\">\n<div style=\"flex: 1; min-width: 250px; background: linear-gradient(135deg, #1E3A8A 0%, #2563EB 100%); display: flex; align-items: center; justify-content: center; padding: 30px; text-align: center;\">\n<div>\n<p style=\"color: white; font-size: 34px; font-family: 'Be Vietnam Pro', sans-serif; font-weight: bold; margin: 0; line-height: 1.1;\">Thu\u00ea VPS<\/p>\n<p style=\"color: #dbeafe; font-size: 15px; font-weight: 600; margin-top: 12px;\">SSD NVMe U.2 \u00b7 CPU Th\u1ebf H\u1ec7 M\u1edbi \u00b7 Ch\u1ed1ng DDoS Chuy\u00ean S\u00e2u<\/p>\n<\/div>\n<\/div>\n<div style=\"flex: 2; padding: 25px; min-width: 300px;\">\n<h3 style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; margin-top: 0; font-size: 20px;\"><span class=\"ez-toc-section\" id=\"Xay-dung-phan-vung-mang-an-toan-cho-du-an-cua-ban\"><\/span>X\u00e2y d\u1ef1ng ph\u00e2n v\u00f9ng m\u1ea1ng an to\u00e0n cho d\u1ef1 \u00e1n c\u1ee7a b\u1ea1n<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify; font-size: 15px; margin-bottom: 15px;\">Khi kh\u1edfi ch\u1ea1y c\u00e1c \u1ee9ng d\u1ee5ng tr\u00ean VPS ri\u00eang bi\u1ec7t, vi\u1ec7c thi\u1ebft l\u1eadp ch\u00ednh x\u00e1c c\u00e1c th\u00f4ng s\u1ed1 IP n\u1ed9i b\u1ed9 gi\u00fap c\u00f4 l\u1eadp t\u00e0i nguy\u00ean kh\u1ecfi c\u00e1c m\u1ed1i \u0111e d\u1ecda b\u00ean ngo\u00e0i. D\u1ecbch v\u1ee5 VPS t\u1ed1c \u0111\u1ed9 cao t\u1ea1i InterData cung c\u1ea5p to\u00e0n quy\u1ec1n root, cho ph\u00e9p b\u1ea1n t\u1ef1 do t\u00f9y bi\u1ebfn c\u1ea5u h\u00ecnh m\u1ea1ng c\u1ee5c b\u1ed9.<\/p>\n<p><a style=\"background: linear-gradient(90deg, #2563EB 0%, #1E3A8A 100%); color: white; padding: 12px 25px; text-decoration: none; font-weight: 600; border-radius: 8px; font-size: 15px; display: inline-block; box-shadow: 0 5px 15px rgba(37,99,235,0.3);\" href=\"https:\/\/interdata.vn\/thue-vps\/\" target=\"_blank\" rel=\"noopener\">XEM B\u1ea2NG GI\u00c1 VPS TI\u1ebeT KI\u1ec6M \u27f6<\/a><\/p>\n<\/div>\n<\/div>\n<h2 id=\"section2\" style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 24px; font-weight: bold; text-align: left; border-left: 5px solid #2563EB; padding-left: 15px; margin-top: 40px; margin-bottom: 20px; line-height: 1.4;\"><span class=\"ez-toc-section\" id=\"2-Cac-Lop-Dia-Chi-IP-Va-Default-Subnet-Mask\"><\/span>2. C\u00e1c L\u1edbp \u0110\u1ecba Ch\u1ec9 IP V\u00e0 Default Subnet Mask<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">\u0110\u1ecba ch\u1ec9 IPv4 ban \u0111\u1ea7u \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i th\u00e0nh 5 l\u1edbp m\u1ea1ng t\u1eeb A \u0111\u1ebfn E d\u1ef1a tr\u00ean quy \u0111\u1ecbnh c\u1ee7a t\u1ed5 ch\u1ee9c qu\u1ea3n l\u00fd Internet. Trong \u0111\u00f3, c\u00e1c l\u1edbp A, B, v\u00e0 C \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng ph\u1ed5 bi\u1ebfn cho c\u00e1c thi\u1ebft b\u1ecb th\u01b0\u01a1ng m\u1ea1i v\u00e0 d\u00e2n d\u1ee5ng tr\u00ean to\u00e0n th\u1ebf gi\u1edbi. M\u1ed7i l\u1edbp m\u1ea1ng n\u00e0y \u0111i k\u00e8m v\u1edbi m\u1ed9t c\u1ea5u h\u00ecnh m\u1eb7t n\u1ea1 m\u1ea1ng m\u1eb7c \u0111\u1ecbnh (Default Subnet Mask) kh\u00e1c nhau nh\u1eb1m c\u00e2n \u0111\u1ed1i gi\u1eefa s\u1ed1 l\u01b0\u1ee3ng ph\u00e2n m\u1ea1ng v\u00e0 s\u1ed1 l\u01b0\u1ee3ng m\u00e1y ch\u1ee7 tr\u00ean m\u1ed7i ph\u00e2n m\u1ea1ng \u0111\u00f3.<\/p>\n<p style=\"text-align: justify;\">H\u1ec7 th\u1ed1ng ph\u00e2n l\u1edbp m\u1ea1ng truy\u1ec1n th\u1ed1ng n\u00e0y gi\u00fap router \u0111\u1ecbnh tuy\u1ebfn nhanh h\u01a1n m\u00e0 kh\u00f4ng c\u1ea7n x\u1eed l\u00fd qu\u00e1 nhi\u1ec1u th\u00f4ng tin ph\u1ee5 tr\u1ee3. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 b\u1ea3ng th\u00f4ng s\u1ed1 ti\u00eau chu\u1ea9n c\u1ee7a ba l\u1edbp m\u1ea1ng ch\u00ednh m\u00e0 b\u1ea1n th\u01b0\u1eddng g\u1eb7p khi thi\u1ebft k\u1ebf m\u1ea1ng LAN ho\u1eb7c c\u1ea5u h\u00ecnh server:<\/p>\n<div style=\"overflow-x: auto; margin-bottom: 25px;\">\n<table style=\"width: 100%; border-collapse: collapse; font-family: 'Be Vietnam Pro', sans-serif; font-size: 14px; text-align: left;\">\n<thead>\n<tr style=\"background-color: #1e3a8a; color: white;\">\n<th style=\"padding: 12px; border: 1px solid #ddd;\">L\u1edbp IP<\/th>\n<th style=\"padding: 12px; border: 1px solid #ddd;\">Kho\u1ea3ng \u0110\u1ecba Ch\u1ec9 \u0110\u1ea7u<\/th>\n<th style=\"padding: 12px; border: 1px solid #ddd;\">Default Subnet Mask<\/th>\n<th style=\"padding: 12px; border: 1px solid #ddd;\">S\u1ed1 L\u01b0\u1ee3ng Host T\u1ed1i \u0110a<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"background-color: #f9f9f9;\">\n<td style=\"padding: 12px; border: 1px solid #ddd; font-weight: bold;\">L\u1edbp A<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">1.0.0.0 \u2013 126.255.255.255<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">255.0.0.0 (\/8)<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">16,777,214<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 12px; border: 1px solid #ddd; font-weight: bold;\">L\u1edbp B<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">128.0.0.0 \u2013 191.255.255.255<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">255.255.0.0 (\/16)<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">65,534<\/td>\n<\/tr>\n<tr style=\"background-color: #f9f9f9;\">\n<td style=\"padding: 12px; border: 1px solid #ddd; font-weight: bold;\">L\u1edbp C<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">192.0.0.0 \u2013 223.255.255.255<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">255.255.255.0 (\/24)<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">254<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p style=\"text-align: justify;\">Ng\u00e0y nay, c\u01a1 ch\u1ebf ph\u00e2n l\u1edbp m\u1ea1ng t\u0129nh n\u00e0y \u0111\u00e3 b\u1ed9c l\u1ed9 \u0111i\u1ec3m y\u1ebfu l\u1edbn v\u1ec1 m\u1eb7t l\u00e3ng ph\u00ed t\u00e0i nguy\u00ean IP. V\u00ed d\u1ee5, n\u1ebfu m\u1ed9t doanh nghi\u1ec7p l\u1edbn c\u1ea7n k\u1ebft n\u1ed1i kho\u1ea3ng 1,000 m\u00e1y ch\u1ee7, h\u1ecd bu\u1ed9c ph\u1ea3i xin c\u1ea5p d\u1ea3i IP L\u1edbp B c\u00f3 s\u1ee9c ch\u1ee9a l\u00ean \u0111\u1ebfn h\u01a1n 65,000 \u0111\u1ecba ch\u1ec9, b\u1ecf ph\u00ed h\u01a1n 64,000 IP c\u00f2n l\u1ea1i. \u0110\u1ec3 kh\u1eafc ph\u1ee5c tri\u1ec7t \u0111\u1ec3 v\u1ea5n \u0111\u1ec1 n\u00e0y, ph\u01b0\u01a1ng ph\u00e1p \u0111\u1ecbnh tuy\u1ebfn kh\u00f4ng ph\u00e2n l\u1edbp (CIDR &#8211; Classless Inter-Domain Routing) \u0111\u00e3 ra \u0111\u1eddi, cho ph\u00e9p linh ho\u1ea1t t\u00f9y bi\u1ebfn s\u1ed1 l\u01b0\u1ee3ng bit m\u1ea1ng \u0111\u1ec3 t\u1ea1o ra nh\u1eefng d\u1ea3i IP c\u00f3 quy m\u00f4 c\u1ef1c k\u1ef3 s\u00e1t v\u1edbi nhu c\u1ea7u th\u1ef1c t\u1ebf.<\/p>\n<h2 id=\"section3\" style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 24px; font-weight: bold; text-align: left; border-left: 5px solid #2563EB; padding-left: 15px; margin-top: 40px; margin-bottom: 20px; line-height: 1.4;\"><span class=\"ez-toc-section\" id=\"3-Cach-Tinh-Subnet-Mask-Chi-Tiet-Tu-Nhi-Phan-Sang-Thap-Phan\"><\/span>3. C\u00e1ch T\u00ednh Subnet Mask Chi Ti\u1ebft T\u1eeb Nh\u1ecb Ph\u00e2n Sang Th\u1eadp Ph\u00e2n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Hi\u1ec3u s\u00e2u c\u00e1ch chuy\u1ec3n \u0111\u1ed5i nh\u1ecb ph\u00e2n l\u00e0 ch\u00eca kh\u00f3a \u0111\u1ec3 l\u00e0m ch\u1ee7 vi\u1ec7c chia m\u1ea1ng con m\u00e0 kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1c c\u00f4ng c\u1ee5 t\u1ef1 \u0111\u1ed9ng tr\u1ef1c tuy\u1ebfn. H\u00e3y nh\u1edb r\u1eb1ng m\u1ed9t octet trong \u0111\u1ecba ch\u1ec9 IP c\u00f3 \u0111\u1ed9 d\u00e0i \u0111\u00fang 8 bit. Gi\u00e1 tr\u1ecb c\u1ee7a t\u1eebng bit t\u01b0\u01a1ng \u1ee9ng v\u1edbi l\u0169y th\u1eeba c\u1ee7a 2 t\u1eeb ph\u1ea3i sang tr\u00e1i, c\u1ee5 th\u1ec3 t\u1eeb bit c\u00f3 tr\u1ecdng s\u1ed1 nh\u1ecf nh\u1ea5t \u0111\u1ebfn l\u1edbn nh\u1ea5t l\u00e0: 1, 2, 4, 8, 16, 32, 64, 128.<\/p>\n<p style=\"text-align: justify;\">Khi ch\u00fang ta m\u01b0\u1ee3n th\u00eam c\u00e1c bit t\u1eeb ph\u1ea7n Host \u0111\u1ec3 g\u00e1n cho ph\u1ea7n Network, gi\u00e1 tr\u1ecb th\u1eadp ph\u00e2n c\u1ee7a octet \u0111\u00f3 s\u1ebd thay \u0111\u1ed5i t\u01b0\u01a1ng \u1ee9ng b\u1eb1ng t\u1ed5ng gi\u00e1 tr\u1ecb c\u00e1c v\u1ecb tr\u00ed bit 1 ho\u1ea1t \u0111\u1ed9ng. V\u00ed d\u1ee5 c\u1ee5 th\u1ec3 d\u01b0\u1edbi \u0111\u00e2y s\u1ebd m\u00f4 t\u1ea3 gi\u00e1 tr\u1ecb th\u1eadp ph\u00e2n thu \u0111\u01b0\u1ee3c khi chuy\u1ec3n \u0111\u1ed5i m\u1ed9t octet t\u1eeb nh\u1ecb ph\u00e2n sang th\u1eadp ph\u00e2n:<\/p>\n<ul style=\"list-style-type: disc; padding-left: 20px; margin-bottom: 25px; color: #1f2937;\">\n<li style=\"margin-bottom: 10px;\"><strong>M\u01b0\u1ee3n 1 bit:<\/strong> <code>10000000<\/code> t\u01b0\u01a1ng \u0111\u01b0\u01a1ng 128 trong h\u1ec7 th\u1eadp ph\u00e2n.<\/li>\n<li style=\"margin-bottom: 10px;\"><strong>M\u01b0\u1ee3n 2 bit:<\/strong> <code>11000000<\/code> t\u01b0\u01a1ng \u0111\u01b0\u01a1ng 128 + 64 = 192 trong h\u1ec7 th\u1eadp ph\u00e2n.<\/li>\n<li style=\"margin-bottom: 10px;\"><strong>M\u01b0\u1ee3n 3 bit:<\/strong> <code>11100000<\/code> t\u01b0\u01a1ng \u0111\u01b0\u01a1ng 128 + 64 + 32 = 224 trong h\u1ec7 th\u1eadp ph\u00e2n.<\/li>\n<li style=\"margin-bottom: 10px;\"><strong>M\u01b0\u1ee3n 4 bit:<\/strong> <code>11110000<\/code> t\u01b0\u01a1ng \u0111\u01b0\u01a1ng 128 + 64 + 32 + 16 = 240 trong h\u1ec7 th\u1eadp ph\u00e2n.<\/li>\n<li style=\"margin-bottom: 10px;\"><strong>M\u01b0\u1ee3n 5 bit:<\/strong> <code>11111000<\/code> t\u01b0\u01a1ng \u0111\u01b0\u01a1ng 128 + 64 + 32 + 16 + 8 = 248 trong h\u1ec7 th\u1eadp ph\u00e2n.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\">Gi\u1ea3 s\u1eed b\u1ea1n c\u1ea7n chia m\u1ea1ng con cho m\u1ed9t d\u1ea3i m\u1ea1ng d\u1ea1ng CIDR k\u00fd hi\u1ec7u l\u00e0 <strong>192.168.1.0\/26<\/strong>. K\u00fd hi\u1ec7u \/26 ch\u1ec9 ra r\u1eb1ng subnet mask n\u00e0y ch\u1ee9a ch\u00ednh x\u00e1c 26 bit 1 li\u00ean t\u1ee5c t\u1eeb tr\u00e1i sang. Ch\u00fang ta s\u1ebd bi\u1ec3u di\u1ec5n c\u1ea5u tr\u00fac n\u00e0y d\u01b0\u1edbi d\u1ea1ng nh\u1ecb ph\u00e2n \u0111\u1ea7y \u0111\u1ee7 g\u1ed3m 4 octet nh\u01b0 sau:<\/p>\n<p style=\"font-family: monospace; background-color: #f3f4f6; padding: 15px; border-radius: 6px; overflow-x: auto; color: #1f2937; line-height: 1.5;\">Nh\u1ecb ph\u00e2n: 11111111.11111111.11111111.11000000<br \/>\nTh\u1eadp ph\u00e2n: 255.255.255.192<\/p>\n<p style=\"text-align: justify;\">Nh\u00ecn v\u00e0o c\u1ea5u tr\u00fac nh\u1ecb ph\u00e2n \u1edf octet th\u1ee9 t\u01b0, ch\u00fang ta th\u1ea5y c\u00f3 2 bit \u0111\u01b0\u1ee3c m\u01b0\u1ee3n l\u00e0m Network ID (gi\u00e1 tr\u1ecb nh\u1ecb ph\u00e2n l\u00e0 11) v\u00e0 c\u00f2n l\u1ea1i 6 bit d\u00e0nh cho Host ID (gi\u00e1 tr\u1ecb nh\u1ecb ph\u00e2n l\u00e0 000000). T\u1eeb \u0111\u00f3, ch\u00fang ta c\u00f3 th\u1ec3 suy ra c\u00e1c th\u00f4ng s\u1ed1 c\u1ee5 th\u1ec3 c\u1ee7a d\u1ea3i m\u1ea1ng n\u00e0y:<\/p>\n<ul style=\"list-style-type: decimal; padding-left: 20px; margin-bottom: 25px; color: #1f2937;\">\n<li style=\"margin-bottom: 10px;\">S\u1ed1 l\u01b0\u1ee3ng m\u1ea1ng con \u0111\u01b0\u1ee3c t\u1ea1o ra l\u00e0: 2^2 = 4 m\u1ea1ng con ri\u00eang bi\u1ec7t.<\/li>\n<li style=\"margin-bottom: 10px;\">T\u1ed5ng s\u1ed1 \u0111\u1ecba ch\u1ec9 IP trong m\u1ed7i m\u1ea1ng con l\u00e0: 2^6 = 64 \u0111\u1ecba ch\u1ec9.<\/li>\n<li style=\"margin-bottom: 10px;\">S\u1ed1 l\u01b0\u1ee3ng m\u00e1y ch\u1ee7 kh\u1ea3 d\u1ee5ng (usable host) th\u1ef1c t\u1ebf trong m\u1ed7i m\u1ea1ng con l\u00e0: 64 &#8211; 2 = 62 m\u00e1y (do ph\u1ea3i lo\u1ea1i b\u1ecf \u0111\u1ecba ch\u1ec9 \u0111\u01b0\u1eddng m\u1ea1ng \u0111\u1ea7u ti\u00ean v\u00e0 \u0111\u1ecba ch\u1ec9 qu\u1ea3ng b\u00e1 broadcast cu\u1ed1i c\u00f9ng).<\/li>\n<\/ul>\n<h2 id=\"section4\" style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 24px; font-weight: bold; text-align: left; border-left: 5px solid #2563EB; padding-left: 15px; margin-top: 40px; margin-bottom: 20px; line-height: 1.4;\"><span class=\"ez-toc-section\" id=\"4-Quy-Tac-Tinh-Nhanh-Subnet-Mask-Phuong-Phap-Magic-Number\"><\/span>4. Quy T\u1eafc T\u00ednh Nhanh Subnet Mask (Ph\u01b0\u01a1ng Ph\u00e1p Magic Number)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Trong th\u1ef1c t\u1ebf v\u1eadn h\u00e0nh m\u1ea1ng hay khi l\u00e0m b\u00e0i thi ch\u1ee9ng ch\u1ec9 CCNA, vi\u1ec7c v\u1ebd nh\u1ecb ph\u00e2n ra gi\u1ea5y r\u1ea5t m\u1ea5t th\u1eddi gian. C\u00e1c k\u1ef9 s\u01b0 h\u1ec7 th\u1ed1ng th\u01b0\u1eddng s\u1eed d\u1ee5ng m\u1ed9t m\u1eb9o t\u00ednh nh\u1ea9m nhanh c\u1ef1c k\u1ef3 hi\u1ec7u qu\u1ea3 g\u1ecdi l\u00e0 ph\u01b0\u01a1ng ph\u00e1p <strong>Magic Number<\/strong> (Con S\u1ed1 K\u1ef3 Di\u1ec7u). Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y gi\u00fap b\u1ea1n x\u00e1c \u0111\u1ecbnh k\u00edch th\u01b0\u1edbc d\u1ea3i m\u1ea1ng v\u00e0 ranh gi\u1edbi c\u00e1c m\u1ea1ng con trong v\u00f2ng ch\u01b0a \u0111\u1ea7y 10 gi\u00e2y.<\/p>\n<p style=\"text-align: justify;\">Quy tr\u00ecnh \u00e1p d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p Magic Number g\u1ed3m c\u00e1c b\u01b0\u1edbc \u0111\u01a1n gi\u1ea3n sau:<\/p>\n<ul style=\"list-style-type: disc; padding-left: 20px; margin-bottom: 25px; color: #1f2937;\">\n<li style=\"margin-bottom: 10px;\"><strong>B\u01b0\u1edbc 1:<\/strong> X\u00e1c \u0111\u1ecbnh octet ch\u1ee9a ranh gi\u1edbi ph\u00e2n chia m\u1ea1ng. \u0110\u1ed1i v\u1edbi c\u00e1c d\u1ea3i m\u1ea1ng c\u00f3 ti\u1ec1n t\u1ed1 CIDR t\u1eeb \/24 \u0111\u1ebfn \/32, octet b\u1ecb \u1ea3nh h\u01b0\u1edfng lu\u00f4n l\u00e0 octet th\u1ee9 t\u01b0.<\/li>\n<li style=\"margin-bottom: 10px;\"><strong>B\u01b0\u1edbc 2:<\/strong> L\u1ea5y ti\u1ec1n t\u1ed1 CIDR tr\u1eeb \u0111i m\u1ed1c l\u1edbp m\u1ea1ng g\u1ea7n nh\u1ea5t \u0111\u1ec3 t\u00ecm s\u1ed1 bit \u0111\u00e3 m\u01b0\u1ee3n. V\u00ed d\u1ee5 v\u1edbi \/28, ta l\u1ea5y 28 &#8211; 24 = 4 bit m\u01b0\u1ee3n.<\/li>\n<li style=\"margin-bottom: 10px;\"><strong>B\u01b0\u1edbc 3:<\/strong> T\u00ednh gi\u00e1 tr\u1ecb c\u1ee7a octet \u0111\u00f3 b\u1eb1ng c\u00e1ch c\u1ed9ng d\u1ed3n c\u00e1c bit m\u01b0\u1ee3n. 4 bit m\u01b0\u1ee3n t\u01b0\u01a1ng \u1ee9ng v\u1edbi 128 + 64 + 32 + 16 = 240. M\u1eb7t n\u1ea1 m\u1ea1ng thu \u0111\u01b0\u1ee3c l\u00e0 255.255.255.240.<\/li>\n<li style=\"margin-bottom: 10px;\"><strong>B\u01b0\u1edbc 4:<\/strong> T\u00ednh Magic Number b\u1eb1ng c\u00f4ng th\u1ee9c l\u1ea5y h\u1eb1ng s\u1ed1 c\u1ed1 \u0111\u1ecbnh l\u00e0 256 tr\u1eeb \u0111i gi\u00e1 tr\u1ecb c\u1ee7a octet bi\u1ebfn \u0111\u1ed5i \u0111\u00f3. Ta c\u00f3: 256 &#8211; 240 = 16.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\">Con s\u1ed1 16 v\u1eeba t\u00ednh \u0111\u01b0\u1ee3c ch\u00ednh l\u00e0 k\u00edch th\u01b0\u1edbc b\u01b0\u1edbc nh\u1ea3y (block size) c\u1ee7a m\u1ed7i m\u1ea1ng con. T\u1eeb \u0111\u00e2y, b\u1ea1n c\u00f3 th\u1ec3 nhanh ch\u00f3ng li\u1ec7t k\u00ea ra danh s\u00e1ch c\u00e1c m\u1ea1ng con b\u1eaft \u0111\u1ea7u t\u1eeb gi\u00e1 tr\u1ecb 0 t\u0103ng d\u1ea7n theo c\u1ea5p s\u1ed1 c\u1ed9ng c\u1ee7a Magic Number:<\/p>\n<div style=\"overflow-x: auto; margin-bottom: 25px;\">\n<table style=\"width: 100%; border-collapse: collapse; font-family: 'Be Vietnam Pro', sans-serif; font-size: 14px; text-align: left;\">\n<thead>\n<tr style=\"background-color: #1e3a8a; color: white;\">\n<th style=\"padding: 12px; border: 1px solid #ddd;\">M\u1ea1ng Con<\/th>\n<th style=\"padding: 12px; border: 1px solid #ddd;\">\u0110\u1ecba Ch\u1ec9 \u0110\u01b0\u1eddng M\u1ea1ng (Network ID)<\/th>\n<th style=\"padding: 12px; border: 1px solid #ddd;\">Kho\u1ea3ng IP G\u00e1n Cho M\u00e1y Ch\u1ee7<\/th>\n<th style=\"padding: 12px; border: 1px solid #ddd;\">\u0110\u1ecba Ch\u1ec9 Qu\u1ea3ng B\u00e1 (Broadcast ID)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"background-color: #f9f9f9;\">\n<td style=\"padding: 12px; border: 1px solid #ddd; font-weight: bold;\">Subnet #1<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd; color: #2563eb; font-weight: 600;\">192.168.1.0<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">192.168.1.1 \u2013 192.168.1.14<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">192.168.1.15<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 12px; border: 1px solid #ddd; font-weight: bold;\">Subnet #2<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd; color: #2563eb; font-weight: 600;\">192.168.1.16<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">192.168.1.17 \u2013 192.168.1.30<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">192.168.1.31<\/td>\n<\/tr>\n<tr style=\"background-color: #f9f9f9;\">\n<td style=\"padding: 12px; border: 1px solid #ddd; font-weight: bold;\">Subnet #3<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd; color: #2563eb; font-weight: 600;\">192.168.1.32<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">192.168.1.33 \u2013 192.168.1.46<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">192.168.1.47<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p style=\"text-align: justify;\">Ph\u01b0\u01a1ng ph\u00e1p Magic Number n\u00e0y lo\u1ea1i b\u1ecf ho\u00e0n to\u00e0n c\u00e1c b\u01b0\u1edbc v\u1ebd nh\u1ecb ph\u00e2n d\u00e0i d\u00f2ng, gi\u1ea3m thi\u1ec3u t\u1ed1i \u0111a c\u00e1c l\u1ed7i t\u00ednh to\u00e1n sai l\u1ec7ch ranh gi\u1edbi m\u1ea1ng, \u0111\u1eb7c bi\u1ec7t h\u1eefu \u00edch khi thi\u1ebft k\u1ebf c\u00e1c s\u01a1 \u0111\u1ed3 m\u1ea1ng ph\u1ee9c t\u1ea1p g\u1ed3m nhi\u1ec1u VLAN kh\u00e1c nhau trong h\u1ec7 th\u1ed1ng m\u00e1y ch\u1ee7 doanh nghi\u1ec7p.<\/p>\n<h2 id=\"section5\" style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 24px; font-weight: bold; text-align: left; border-left: 5px solid #2563EB; padding-left: 15px; margin-top: 40px; margin-bottom: 20px; line-height: 1.4;\"><span class=\"ez-toc-section\" id=\"5-Ung-Dung-Thuc-Te-Cau-Hinh-Subnet-Mask-Tren-He-Dieu-Hanh-Docker\"><\/span>5. \u1ee8ng D\u1ee5ng Th\u1ef1c T\u1ebf: C\u1ea5u H\u00ecnh Subnet Mask Tr\u00ean H\u1ec7 \u0110i\u1ec1u H\u00e0nh &amp; Docker<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Khi b\u1ea1n thu\u00ea m\u00e1y ch\u1ee7 ho\u1eb7c c\u00e0i \u0111\u1eb7t \u1ea3o h\u00f3a, vi\u1ec7c g\u00e1n th\u00f4ng s\u1ed1 m\u1ea1ng l\u00e0 b\u01b0\u1edbc b\u1eaft bu\u1ed9c \u0111\u1ea7u ti\u00ean. T\u00f9y thu\u1ed9c v\u00e0o m\u00f4i tr\u01b0\u1eddng l\u00e0 Linux, Windows hay c\u00e1c container ch\u1ea1y trong Docker, c\u00fa ph\u00e1p v\u00e0 c\u00e1ch th\u1ee9c \u00e1p d\u1ee5ng c\u1ea5u h\u00ecnh m\u1eb7t n\u1ea1 m\u1ea1ng s\u1ebd c\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t.<\/p>\n<h3 style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 20px; font-weight: 600; margin-top: 25px; margin-bottom: 15px;\"><span class=\"ez-toc-section\" id=\"A-Thiet-lap-mang-tinh-tren-Linux-Ubuntu-Server-dung-Netplan\"><\/span>A. Thi\u1ebft l\u1eadp m\u1ea1ng t\u0129nh tr\u00ean Linux (Ubuntu Server d\u00f9ng Netplan)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify;\">T\u1eeb phi\u00ean b\u1ea3n Ubuntu 18.04 tr\u1edf \u0111i, h\u1ec7 th\u1ed1ng s\u1eed d\u1ee5ng c\u00f4ng c\u1ee5 Netplan \u0111\u1ec3 qu\u1ea3n l\u00fd c\u1ea5u h\u00ecnh m\u1ea1ng qua c\u00e1c file YAML. File c\u1ea5u h\u00ecnh th\u01b0\u1eddng n\u1eb1m trong th\u01b0 m\u1ee5c <code>\/etc\/netplan\/<\/code>. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 v\u00ed d\u1ee5 c\u1ea5u h\u00ecnh g\u00e1n m\u1ed9t IP t\u0129nh \u0111i k\u00e8m d\u1ea3i m\u1ea1ng \/24:<\/p>\n<pre>network:\r\n  version: 2\r\n  renderer: networkd\r\n  ethernets:\r\n    eth0:\r\n      dhcp4: no\r\n      addresses:\r\n        - 192.168.1.15\/24\r\n      nameservers:\r\n        addresses: [8.8.8.8, 1.1.1.1]\r\n      routes:\r\n        - to: default\r\n          via: 192.168.1.1<\/pre>\n<p style=\"text-align: justify;\">Sau khi ch\u1ec9nh s\u1eeda c\u1ea5u h\u00ecnh xong, b\u1ea1n c\u1ea7n ch\u1ea1y l\u1ec7nh sau \u0111\u1ec3 ki\u1ec3m tra l\u1ed7i c\u00fa ph\u00e1p v\u00e0 \u00e1p d\u1ee5ng thi\u1ebft l\u1eadp m\u1edbi v\u00e0o h\u1ec7 th\u1ed1ng card m\u1ea1ng th\u1ef1c t\u1ebf:<\/p>\n<p style=\"font-family: monospace; background-color: #f3f4f6; padding: 12px; border-radius: 6px; overflow-x: auto; color: #d97706; font-weight: bold;\">sudo netplan apply<\/p>\n<h3 style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 20px; font-weight: 600; margin-top: 25px; margin-bottom: 15px;\"><span class=\"ez-toc-section\" id=\"B-Cau-hinh-nhanh-qua-giao-dien-dong-lenh-Windows-Server\"><\/span>B. C\u1ea5u h\u00ecnh nhanh qua giao di\u1ec7n d\u00f2ng l\u1ec7nh Windows Server<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify;\">\u0110\u1ed1i v\u1edbi h\u1ec7 \u0111i\u1ec1u h\u00e0nh Windows Server, ngo\u00e0i vi\u1ec7c click chu\u1ed9t trong giao di\u1ec7n c\u1ea5u h\u00ecnh Card m\u1ea1ng truy\u1ec1n th\u1ed1ng, b\u1ea1n c\u00f3 th\u1ec3 th\u1ef1c thi nhanh ch\u00f3ng th\u00f4ng qua c\u1eeda s\u1ed5 PowerShell ho\u1eb7c CMD b\u1eb1ng c\u00f4ng c\u1ee5 Netsh:<\/p>\n<pre style=\"background-color: #1e293b; color: #f8fafc; padding: 18px; border-radius: 8px; font-size: 14px; overflow-x: auto; line-height: 1.6; border: 1px solid #334155;\">netsh interface ipv4 set address name=\"Ethernet\" static 192.168.1.15 255.255.255.0 192.168.1.1<\/pre>\n<h3 style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 20px; font-weight: 600; margin-top: 25px; margin-bottom: 15px;\"><span class=\"ez-toc-section\" id=\"C-Phan-vung-mang-doc-lap-trong-moi-truong-Docker-Container\"><\/span>C. Ph\u00e2n v\u00f9ng m\u1ea1ng \u0111\u1ed9c l\u1eadp trong m\u00f4i tr\u01b0\u1eddng Docker Container<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify;\">M\u1eb7c \u0111\u1ecbnh, Docker t\u1ea1o ra c\u00e1c bridge network t\u1ef1 \u0111\u1ed9ng \u0111\u1ec3 c\u00e1c container giao ti\u1ebfp n\u1ed9i b\u1ed9. Tuy nhi\u00ean, n\u1ebfu mu\u1ed1n ph\u00e2n v\u00f9ng c\u00e1c \u1ee9ng d\u1ee5ng c\u01a1 s\u1edf d\u1eef li\u1ec7u nh\u1ea1y c\u1ea3m n\u1eb1m t\u00e1ch bi\u1ec7t ho\u00e0n to\u00e0n v\u1edbi API web, b\u1ea1n n\u00ean t\u1ef1 \u0111\u1ecbnh ngh\u0129a m\u1ed9t d\u1ea3i m\u1ea1ng con t\u00f9y ch\u1ec9nh b\u1eb1ng d\u00f2ng l\u1ec7nh sau:<\/p>\n<pre style=\"background-color: #1e293b; color: #f8fafc; padding: 18px; border-radius: 8px; font-size: 14px; overflow-x: auto; line-height: 1.6; border: 1px solid #334155;\">docker network create --driver bridge --subnet 172.20.0.0\/24 internal_secure_net<\/pre>\n<p style=\"text-align: justify;\">C\u1ea5u h\u00ecnh n\u00e0y \u0111\u1ea3m b\u1ea3o r\u1eb1ng c\u00e1c container k\u1ebft n\u1ed1i v\u00e0o ph\u00e2n m\u1ea1ng <code>internal_secure_net<\/code> s\u1ebd t\u1ef1 \u0111\u1ed9ng nh\u1eadn c\u00e1c IP n\u1eb1m trong d\u1ea3i t\u1eeb <code>172.20.0.1<\/code> \u0111\u1ebfn <code>172.20.0.254<\/code>, c\u00e1ch ly ho\u00e0n to\u00e0n kh\u1ecfi l\u01b0u l\u01b0\u1ee3ng r\u00e1c t\u1eeb c\u00e1c c\u1ee5m container c\u00f4ng c\u1ed9ng kh\u00e1c.<\/p>\n<h2 id=\"section6\" style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 24px; font-weight: bold; text-align: left; border-left: 5px solid #2563EB; padding-left: 15px; margin-top: 40px; margin-bottom: 20px; line-height: 1.4;\"><span class=\"ez-toc-section\" id=\"6-Cac-Loi-Thuong-Gap-Khi-Chia-Mang-Con-Va-Cach-Khac-Phuc\"><\/span>6. C\u00e1c L\u1ed7i Th\u01b0\u1eddng G\u1eb7p Khi Chia M\u1ea1ng Con V\u00e0 C\u00e1ch Kh\u1eafc Ph\u1ee5c<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Trong qu\u00e1 tr\u00ecnh v\u1eadn h\u00e0nh h\u1ea1 t\u1ea7ng m\u00e1y ch\u1ee7 n\u1ed9i b\u1ed9 ho\u1eb7c x\u00e2y d\u1ef1ng m\u1ea1ng \u1ea3o h\u00f3a n\u1ed9i h\u1ea1t, c\u00e1c l\u1ed7i li\u00ean quan \u0111\u1ebfn \u0111\u1ecbnh c\u1ea5u h\u00ecnh sai d\u1ea3i m\u1ea1ng IP x\u1ea3y ra kh\u00e1 ph\u1ed5 bi\u1ebfn. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 b\u1ea3ng ph\u00e2n t\u00edch chi ti\u1ebft c\u00e1c t\u00ecnh hu\u1ed1ng l\u1ed7i th\u1ef1c t\u1ebf, nguy\u00ean nh\u00e2n ti\u1ec1m \u1ea9n v\u00e0 gi\u1ea3i ph\u00e1p x\u1eed l\u00fd tri\u1ec7t \u0111\u1ec3:<\/p>\n<div style=\"overflow-x: auto; margin-bottom: 25px;\">\n<table style=\"width: 100%; border-collapse: collapse; font-family: 'Be Vietnam Pro', sans-serif; font-size: 14px; text-align: left;\">\n<thead>\n<tr style=\"background-color: #1e3a8a; color: white;\">\n<th style=\"padding: 12px; border: 1px solid #ddd; width: 25%;\">Tri\u1ec7u Ch\u1ee9ng S\u1ef1 C\u1ed1<\/th>\n<th style=\"padding: 12px; border: 1px solid #ddd; width: 35%;\">Nguy\u00ean Nh\u00e2n Kh\u1ea3 Nghi<\/th>\n<th style=\"padding: 12px; border: 1px solid #ddd; width: 40%;\">Quy Tr\u00ecnh X\u1eed L\u00fd Th\u1ef1c T\u1ebf<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"background-color: #f9f9f9;\">\n<td style=\"padding: 12px; border: 1px solid #ddd; font-weight: bold; color: #c2410c;\">M\u1ea5t k\u1ebft n\u1ed1i ch\u1eadp ch\u1eddn gi\u1eefa hai m\u00e1y ch\u1ee7 chung switch v\u1eadt l\u00fd.<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">Hai d\u1ea3i m\u1ea1ng con b\u1ecb ghi \u0111\u00e8 ranh gi\u1edbi l\u00ean nhau (Overlapping Subnets) do t\u00ednh to\u00e1n sai Magic Number khi chia VLAN.<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">D\u00f9ng l\u1ec7nh <code>ip route show<\/code> tr\u00ean Linux ho\u1eb7c <code>route print<\/code> tr\u00ean Windows \u0111\u1ec3 r\u00e0 so\u00e1t b\u1ea3ng \u0111\u1ecbnh tuy\u1ebfn t\u0129nh, \u0111i\u1ec1u ch\u1ec9nh l\u1ea1i ti\u1ec1n t\u1ed1 CIDR c\u1ee7a card m\u1ea1ng b\u1ecb tr\u00f9ng.<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 12px; border: 1px solid #ddd; font-weight: bold; color: #c2410c;\">Kh\u00f4ng th\u1ec3 k\u1ebft n\u1ed1i ra internet d\u00f9 ping th\u00f4ng n\u1ed9i m\u1ea1ng.<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">\u0110\u1ecba ch\u1ec9 Default Gateway n\u1eb1m ngo\u00e0i ph\u1ea1m vi d\u1ea3i m\u1ea1ng \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a b\u1edfi subnet mask hi\u1ec7n t\u1ea1i.<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">Ki\u1ec3m tra l\u1ea1i xem IP Gateway c\u00f3 \u0111\u00fang d\u1ea3i m\u1ea1ng con c\u1ee7a card m\u1ea1ng hay ch\u01b0a. V\u00ed d\u1ee5, d\u1ea3i \/29 ch\u1ec9 ch\u1ea1y t\u1eeb .1 \u0111\u1ebfn .6, n\u1ebfu \u0111\u1eb7t Gateway l\u00e0 .254 s\u1ebd d\u1eabn \u0111\u1ebfn l\u1ed7i \u0111\u1ecbnh tuy\u1ebfn.<\/td>\n<\/tr>\n<tr style=\"background-color: #f9f9f9;\">\n<td style=\"padding: 12px; border: 1px solid #ddd; font-weight: bold; color: #c2410c;\">Thi\u1ebft b\u1ecb nh\u1eadn \u0111\u01b0\u1ee3c IP nh\u01b0ng b\u00e1o l\u1ed7i xung \u0111\u1ed9t \u0111\u1ecba ch\u1ec9 IP.<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">Qu\u1ea3n tr\u1ecb vi\u00ean v\u00f4 t\u00ecnh c\u1ea5u h\u00ecnh g\u00e1n nh\u1ea7m \u0111\u1ecba ch\u1ec9 Network ID ho\u1eb7c Broadcast ID cho m\u1ed9t thi\u1ebft b\u1ecb th\u1ef1c t\u1ebf.<\/td>\n<td style=\"padding: 12px; border: 1px solid #ddd;\">B\u1ecf g\u00e1n c\u00e1c IP \u0111u\u00f4i .0 ho\u1eb7c .255 (\u0111\u1ed1i v\u1edbi d\u1ea3i \/24 m\u1eb7c \u0111\u1ecbnh). \u0110\u1ea3m b\u1ea3o ch\u1ec9 c\u1ea5p ph\u00e1t c\u00e1c IP thu\u1ed9c kho\u1ea3ng kh\u1ea3 d\u1ee5ng (Usable Host).<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div style=\"display: flex; flex-wrap: wrap; background-color: #fff; border: 1.5px solid #BFDBFE; box-shadow: 0 8px 20px rgba(37,99,235,0.08); border-radius: 12px; overflow: hidden; margin: 35px 0;\">\n<div style=\"flex: 1; min-width: 250px; background: linear-gradient(135deg, #1E3A8A 0%, #2563EB 100%); display: flex; align-items: center; justify-content: center; padding: 30px; text-align: center;\">\n<div>\n<p style=\"color: white; font-size: 34px; font-family: 'Be Vietnam Pro', sans-serif; font-weight: bold; margin: 0; line-height: 1.1;\">Cloud Server<\/p>\n<p style=\"color: #dbeafe; font-size: 15px; font-weight: 600; margin-top: 12px;\">B\u0103ng Th\u00f4ng L\u1edbn \u00b7 Sao L\u01b0u \u0110\u1ecbnh K\u1ef3 \u00b7 Kh\u1edfi T\u1ea1o Nhanh<\/p>\n<\/div>\n<\/div>\n<div style=\"flex: 2; padding: 25px; min-width: 300px;\">\n<h3 style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; margin-top: 0; font-size: 20px;\"><span class=\"ez-toc-section\" id=\"Linh-hoat-mo-rong-tai-nguyen-mang-tren-dam-may\"><\/span>Linh ho\u1ea1t m\u1edf r\u1ed9ng t\u00e0i nguy\u00ean m\u1ea1ng tr\u00ean \u0111\u00e1m m\u00e2y<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify; font-size: 15px; margin-bottom: 15px;\">H\u1ec7 th\u1ed1ng \u1ee9ng d\u1ee5ng c\u1ee7a doanh nghi\u1ec7p \u0111ang ng\u00e0y m\u1ed9t l\u1edbn m\u1ea1nh \u0111\u00f2i h\u1ecfi c\u00e1c t\u00ednh n\u0103ng t\u1ea1o VPC, chia VLAN \u0111\u1ed9c l\u1eadp gi\u1eefa c\u1ee5m database v\u00e0 front-end. Gi\u1ea3i ph\u00e1p Cloud Server t\u1ea1i InterData cho ph\u00e9p b\u1ea1n \u0111i\u1ec1u ch\u1ec9nh t\u00e0i nguy\u00ean t\u1ee9c th\u00ec, h\u1ed7 tr\u1ee3 k\u1ebft n\u1ed1i m\u1ea1ng n\u1ed9i b\u1ed9 t\u1ed1c \u0111\u1ed9 cao an to\u00e0n.<\/p>\n<p><a style=\"background: linear-gradient(90deg, #2563EB 0%, #1E3A8A 100%); color: white; padding: 12px 25px; text-decoration: none; font-weight: 600; border-radius: 8px; font-size: 15px; display: inline-block; box-shadow: 0 5px 15px rgba(37,99,235,0.3);\" href=\"https:\/\/interdata.vn\/cloud-server\/\" target=\"_blank\" rel=\"noopener\">XEM B\u1ea2NG GI\u00c1 CLOUD SERVER \u27f6<\/a><\/p>\n<\/div>\n<\/div>\n<h2 id=\"section7\" style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 24px; font-weight: bold; text-align: left; border-left: 5px solid #2563EB; padding-left: 15px; margin-top: 40px; margin-bottom: 20px; line-height: 1.4;\"><span class=\"ez-toc-section\" id=\"7-Cau-Hoi-Thuong-Gap-FAQs-Ve-Mang-Con\"><\/span>7. C\u00e2u H\u1ecfi Th\u01b0\u1eddng G\u1eb7p (FAQs) V\u1ec1 M\u1ea1ng Con<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Nh\u1eb1m gi\u00fap b\u1ea1n \u0111\u1ecdc c\u1ee7ng c\u1ed1 th\u00eam c\u00e1c ki\u1ebfn th\u1ee9c th\u1ef1c t\u1ebf trong qu\u00e1 tr\u00ecnh l\u00e0m vi\u1ec7c v\u1edbi h\u1ec7 th\u1ed1ng \u0111\u1ecbnh tuy\u1ebfn, d\u01b0\u1edbi \u0111\u00e2y l\u00e0 nh\u1eefng gi\u1ea3i \u0111\u00e1p ng\u1eafn g\u1ecdn cho c\u00e1c th\u1eafc m\u1eafc th\u01b0\u1eddng th\u1ea5y nh\u1ea5t:<\/p>\n<ul style=\"list-style-type: none; padding-left: 0; margin-bottom: 25px; color: #1f2937;\">\n<li style=\"margin-bottom: 20px; background-color: #f8fafc; padding: 15px; border-radius: 8px; border-left: 4px solid #1E3A8A;\">\n<p style=\"font-weight: bold; color: #1e3a8a; margin-top: 0; margin-bottom: 8px;\">C\u00e2u h\u1ecfi 1: Hai thi\u1ebft b\u1ecb c\u00f3 th\u1ec3 k\u1ebft n\u1ed1i v\u1edbi nhau n\u1ebfu kh\u00e1c subnet mask kh\u00f4ng?<\/p>\n<p style=\"text-align: justify; margin: 0; font-size: 14px;\">N\u1ebfu hai m\u00e1y ch\u1ee7 k\u1ebft n\u1ed1i tr\u1ef1c ti\u1ebfp v\u00e0o c\u00f9ng m\u1ed9t thi\u1ebft b\u1ecb switch m\u00e0 kh\u00f4ng c\u00f3 c\u1ea5u h\u00ecnh \u0111\u1ecbnh tuy\u1ebfn (routing) \u1edf Layer 3, ch\u00fang s\u1ebd kh\u00f4ng th\u1ec3 giao ti\u1ebfp tr\u1ef1c ti\u1ebfp v\u1edbi nhau khi c\u1ea5u h\u00ecnh kh\u00e1c subnet mask. L\u00fd do l\u00e0 v\u00ec g\u00f3i tin ARP qu\u1ea3ng b\u00e1 y\u00eau c\u1ea7u t\u00ecm \u0111\u1ecba ch\u1ec9 MAC s\u1ebd b\u1ecb ch\u1eb7n l\u1ea1i do router ho\u1eb7c card m\u1ea1ng nh\u1eadn di\u1ec7n ch\u00fang thu\u1ed9c hai ph\u00e2n v\u00f9ng m\u1ea1ng \u0111\u1ed9c l\u1eadp.<\/p>\n<\/li>\n<li style=\"margin-bottom: 20px; background-color: #f8fafc; padding: 15px; border-radius: 8px; border-left: 4px solid #1E3A8A;\">\n<p style=\"font-weight: bold; color: #1e3a8a; margin-top: 0; margin-bottom: 8px;\">C\u00e2u h\u1ecfi 2: T\u1ea1i sao lu\u00f4n ph\u1ea3i tr\u1eeb \u0111i 2 \u0111\u1ecba ch\u1ec9 IP khi t\u00ednh s\u1ed1 m\u00e1y ch\u1ee7 kh\u1ea3 d\u1ee5ng?<\/p>\n<p style=\"text-align: justify; margin: 0; font-size: 14px;\">Trong b\u1ea5t k\u1ef3 m\u1ea1ng con n\u00e0o, \u0111\u1ecba ch\u1ec9 IP \u0111\u1ea7u ti\u00ean (t\u1ea5t c\u1ea3 c\u00e1c bit c\u1ee7a Host ID b\u1eb1ng 0) lu\u00f4n \u0111\u01b0\u1ee3c d\u00e0nh ri\u00eang \u0111\u1ec3 \u0111\u1ea1i di\u1ec7n cho Network ID. \u0110\u1ecba ch\u1ec9 IP cu\u1ed1i c\u00f9ng (t\u1ea5t c\u1ea3 c\u00e1c bit c\u1ee7a Host ID b\u1eb1ng 1) \u0111\u01b0\u1ee3c d\u00f9ng l\u00e0m Broadcast ID \u0111\u1ec3 g\u1eedi d\u1eef li\u1ec7u \u0111\u1ed3ng lo\u1ea1t cho t\u1ea5t c\u1ea3 thi\u1ebft b\u1ecb trong ph\u00e2n m\u1ea1ng \u0111\u00f3. Do \u0111\u00f3, hai \u0111\u1ecba ch\u1ec9 n\u00e0y kh\u00f4ng \u0111\u01b0\u1ee3c ph\u00e9p g\u00e1n cho c\u00e1c thi\u1ebft b\u1ecb th\u1ef1c t\u1ebf.<\/p>\n<\/li>\n<li style=\"margin-bottom: 20px; background-color: #f8fafc; padding: 15px; border-radius: 8px; border-left: 4px solid #1E3A8A;\">\n<p style=\"font-weight: bold; color: #1e3a8a; margin-top: 0; margin-bottom: 8px;\">C\u00e2u h\u1ecfi 3: K\u00fd hi\u1ec7u ti\u1ec1n t\u1ed1 CIDR l\u00e0 g\u00ec v\u00e0 n\u00f3 kh\u00e1c g\u00ec so v\u1edbi subnet mask th\u00f4ng th\u01b0\u1eddng?<\/p>\n<p style=\"text-align: justify; margin: 0; font-size: 14px;\">CIDR l\u00e0 c\u00e1ch vi\u1ebft r\u00fat g\u1ecdn bi\u1ec3u di\u1ec5n s\u1ed1 l\u01b0\u1ee3ng bit m\u1ea1ng b\u1eb1ng m\u1ed9t d\u1ea5u g\u1ea1ch ch\u00e9o \u0111i k\u00e8m m\u1ed9t con s\u1ed1 c\u1ee5 th\u1ec3, v\u00ed d\u1ee5 nh\u01b0 \/24 thay v\u00ec ph\u1ea3i vi\u1ebft \u0111\u1ea7y \u0111\u1ee7 l\u00e0 255.255.255.0. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y gi\u00fap ghi ch\u00e9p c\u1ea5u h\u00ecnh t\u01b0\u1eddng l\u1eeda, thi\u1ebft b\u1ecb \u0111\u1ecbnh tuy\u1ebfn tr\u1edf n\u00ean ng\u1eafn g\u1ecdn v\u00e0 tr\u1ef1c quan h\u01a1n r\u1ea5t nhi\u1ec1u.<\/p>\n<\/li>\n<li style=\"margin-bottom: 20px; background-color: #f8fafc; padding: 15px; border-radius: 8px; border-left: 4px solid #1E3A8A;\">\n<p style=\"font-weight: bold; color: #1e3a8a; margin-top: 0; margin-bottom: 8px;\">C\u00e2u h\u1ecfi 4: Khi n\u00e0o t\u00f4i n\u00ean s\u1eed d\u1ee5ng m\u1eb7t n\u1ea1 m\u1ea1ng \/30 cho h\u1ec7 th\u1ed1ng?<\/p>\n<p style=\"text-align: justify; margin: 0; font-size: 14px;\">D\u1ea3i m\u1ea1ng \/30 ch\u1ec9 cung c\u1ea5p \u0111\u00fang 2 IP kh\u1ea3 d\u1ee5ng cho m\u00e1y ch\u1ee7. \u0110\u1ecbnh d\u1ea1ng n\u00e0y c\u1ef1c k\u1ef3 h\u1eefu \u00edch cho c\u00e1c k\u1ebft n\u1ed1i \u0111i\u1ec3m-\u0111i\u1ec3m (Point-to-Point) k\u1ebft n\u1ed1i tr\u1ef1c ti\u1ebfp gi\u1eefa hai c\u1ed5ng c\u1ee7a hai router kh\u00e1c nhau, gi\u00fap ti\u1ebft ki\u1ec7m t\u1ed1i \u0111a kh\u00f4ng gian \u0111\u1ecba ch\u1ec9 IP c\u00f4ng c\u1ed9ng (Public IP) \u0111\u1eaft \u0111\u1ecf.<\/p>\n<\/li>\n<li style=\"margin-bottom: 20px; background-color: #f8fafc; padding: 15px; border-radius: 8px; border-left: 4px solid #1E3A8A;\">\n<p style=\"font-weight: bold; color: #1e3a8a; margin-top: 0; margin-bottom: 8px;\">C\u00e2u h\u1ecfi 5: C\u1ea5u h\u00ecnh subnet mask sai tr\u00ean thi\u1ebft b\u1ecb th\u00ec c\u00f3 g\u00e2y r\u1ee7i ro m\u1ea5t an to\u00e0n th\u00f4ng tin kh\u00f4ng?<\/p>\n<p style=\"text-align: justify; margin: 0; font-size: 14px;\">C\u00f3. C\u1ea5u h\u00ecnh m\u1eb7t n\u1ea1 m\u1ea1ng qu\u00e1 r\u1ed9ng s\u1ebd l\u00e0m t\u0103ng r\u1ee7i ro h\u1ee9ng ch\u1ecbu c\u00e1c \u0111\u1ee3t qu\u00e9t IP \u0111\u1ed9c h\u1ea1i t\u1eeb c\u00e1c thi\u1ebft b\u1ecb kh\u00e1c trong c\u00f9ng m\u1ea1ng LAN v\u1eadt l\u00fd, \u0111\u1ed3ng th\u1eddi l\u00e0m b\u00f9ng n\u1ed5 c\u00e1c g\u00f3i tin r\u00e1c (Broadcast Storm) g\u00e2y suy gi\u1ea3m nghi\u00eam tr\u1ecdng b\u0103ng th\u00f4ng kh\u1ea3 d\u1ee5ng c\u1ee7a h\u1ec7 th\u1ed1ng m\u00e1y ch\u1ee7 n\u1ed9i b\u1ed9.<\/p>\n<\/li>\n<\/ul>\n<div style=\"border-top: 2px dashed #BFDBFE; margin-top: 50px; padding-top: 30px;\">\n<h3 style=\"font-family: 'Be Vietnam Pro', sans-serif; color: #1e3a8a; font-size: 22px; font-weight: bold; margin-bottom: 15px;\"><span class=\"ez-toc-section\" id=\"Tong-Ket-Kien-Thuc-Ve-Mat-Na-Mang\"><\/span>T\u1ed5ng K\u1ebft Ki\u1ebfn Th\u1ee9c V\u1ec1 M\u1eb7t N\u1ea1 M\u1ea1ng<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify;\">L\u00e0m ch\u1ee7 k\u1ef9 thu\u1eadt ph\u00e2n chia d\u1ea3i m\u1ea1ng v\u00e0 t\u00ednh to\u00e1n ch\u00ednh x\u00e1c <strong>subnet mask<\/strong> l\u00e0 n\u1ec1n t\u1ea3ng c\u1ed1t l\u00f5i gi\u00fap c\u00e1c k\u1ef9 s\u01b0 qu\u1ea3n tr\u1ecb h\u1ec7 th\u1ed1ng t\u1ed1i \u01b0u h\u00f3a lu\u1ed3ng d\u1eef li\u1ec7u, ng\u0103n ch\u1eb7n tri\u1ec7t \u0111\u1ec3 c\u00e1c r\u1ee7i ro b\u1ea3o m\u1eadt ti\u1ec1m \u1ea9n. Vi\u1ec7c chia m\u1ea1ng con h\u1ee3p l\u00fd gi\u00fap doanh nghi\u1ec7p x\u00e2y d\u1ef1ng m\u00f4 h\u00ecnh ph\u00f2ng v\u1ec7 chi\u1ec1u s\u00e2u v\u1eefng ch\u1eafc ngay t\u1ea1i l\u1edbp Layer 3.<\/p>\n<div style=\"background: #EFF6FF; border: 1px solid #2563EB; padding: 30px; margin-top: 25px; border-radius: 12px; text-align: center;\">\n<p style=\"font-family: 'Be Vietnam Pro', sans-serif; font-size: 20px; font-weight: bold; color: #1e3a8a; margin-top: 0;\">Kh\u1edfi t\u1ea1o h\u1ea1 t\u1ea7ng m\u1ea1ng an to\u00e0n cho m\u00e1y ch\u1ee7 c\u1ee7a b\u1ea1n<\/p>\n<p style=\"font-size: 15px; margin-bottom: 20px; color: #4b5563;\">\u0110\u1ec3 tri\u1ec3n khai c\u00e1c c\u1ea5u h\u00ecnh ph\u00e2n v\u00f9ng m\u1ea1ng LAN ph\u1ee9c t\u1ea1p, h\u00e3y l\u1ef1a ch\u1ecdn h\u1ec7 th\u1ed1ng VPS ch\u1ea5t l\u01b0\u1ee3ng cao c\u1ee7a InterData l\u00e0m b\u1ec7 \u0111\u1ee1 v\u1eefng ch\u1eafc.<\/p>\n<p><a style=\"background: #2563EB; color: #ffffff; padding: 12px 30px; text-decoration: none; font-weight: 600; border-radius: 6px; display: inline-block;\" href=\"https:\/\/interdata.vn\/thue-vps\/\" target=\"_blank\" rel=\"noopener\">THU\u00ca VPS C\u1ea4U H\u00ccNH CAO NGAY \u27f6<\/a><\/p>\n<\/div>\n<\/div>\n<p style=\"text-align: justify; font-size: 13px; font-style: italic; color: #6b7280; margin-top: 30px; border-top: 1px solid #E5E7EB; padding-top: 15px;\"><span style=\"font-size: 100%;\"><em>L\u01b0u \u00fd: M\u1ecdi th\u00f4ng tin h\u01b0\u1edbng d\u1eabn k\u1ef9 thu\u1eadt trong b\u00e0i vi\u1ebft n\u00e0y ch\u1ec9 mang t\u00ednh ch\u1ea5t tham kh\u1ea3o chung. C\u00e1c c\u00e2u l\u1ec7nh c\u1ea5u h\u00ecnh v\u00e0 c\u00e1ch g\u00e1n \u0111\u1ecba ch\u1ec9 IP th\u1ef1c t\u1ebf c\u00f3 th\u1ec3 thay \u0111\u1ed5i t\u00f9y thu\u1ed9c v\u00e0o h\u1ec7 \u0111i\u1ec1u h\u00e0nh, phi\u00ean b\u1ea3n h\u1ea1t nh\u00e2n ph\u1ea7n m\u1ec1m c\u0169ng nh\u01b0 ki\u1ebfn tr\u00fac m\u1ea1ng v\u1eadt l\u00fd c\u1ee7a b\u1ea1n. Ng\u01b0\u1eddi d\u00f9ng n\u00ean th\u1ef1c hi\u1ec7n ki\u1ec3m th\u1eed tr\u00ean c\u00e1c m\u00f4i tr\u01b0\u1eddng th\u1eed nghi\u1ec7m v\u00e0 ti\u1ebfn h\u00e0nh sao l\u01b0u to\u00e0n b\u1ed9 d\u1eef li\u1ec7u c\u1ea5u h\u00ecnh tr\u01b0\u1edbc khi ti\u1ebfn h\u00e0nh thay \u0111\u1ed5i tr\u00ean h\u1ec7 th\u1ed1ng v\u1eadn h\u00e0nh ch\u00ednh th\u1ee9c.<\/em><\/span><\/p>\n\n\n<style>\n.interdata-plan-carousel{--blue:#005bea;--blue-dark:#004dcc;--text:#071832;--border:#d8e6fb;--bg:#f3f8ff;container-type:inline-size;background:var(--bg);padding:14px 12px;overflow:hidden}\n.interdata-carousel-heading{color:#003fbd;font-size:18px;line-height:1.35;font-weight:800;text-align:center;margin:0 0 14px}\n.interdata-plan-track{display:flex;gap:12px;overflow-x:auto;scroll-snap-type:x mandatory;padding:0 0 8px;-webkit-overflow-scrolling:touch;scrollbar-width:none}\n.interdata-plan-track::-webkit-scrollbar{display:none}\n.interdata-plan-card,.interdata-plan-card *{box-sizing:border-box}\n.interdata-plan-card{flex:0 0 calc(25% - 9px);min-width:205px;background:#fff;border:1px solid var(--border);border-radius:8px;padding:18px 14px 14px;min-height:382px;display:flex;flex-direction:column;scroll-snap-align:start;box-shadow:0 5px 14px rgba(0,62,145,.08)}\n.interdata-plan-title{color:var(--blue-dark);font-size:17px;line-height:1.25;font-weight:800;text-align:center;margin:0 0 8px}\n.interdata-plan-price{color:var(--blue-dark);font-size:32px;line-height:1;font-weight:900;text-align:center;margin-bottom:14px;white-space:nowrap;letter-spacing:0}\n.interdata-plan-price span{font-size:12px;font-weight:800;margin-left:2px}\n.interdata-plan-badge{align-self:center;display:inline-flex;align-items:center;justify-content:center;background:#ff3934;color:#fff;border-radius:5px;padding:8px 10px;font-size:10px;line-height:1;font-weight:800;margin-bottom:18px;white-space:nowrap}\n.interdata-plan-features{list-style:none!important;padding:0!important;margin:0!important}\n.interdata-plan-features li{display:flex;gap:8px;align-items:flex-start;color:var(--text);font-size:13px;line-height:1.35;font-weight:700;text-align:left;margin:0 0 11px!important;padding:0!important}\n.interdata-plan-icon{width:15px;min-width:15px;height:15px;color:#0069ff;margin-top:2px}\n.interdata-plan-icon svg{display:block;width:100%;height:100%;fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}\n.interdata-plan-spacer{flex:1}\n.interdata-plan-button{display:flex;align-items:center;justify-content:center;min-height:44px;width:100%;background:var(--blue);color:#fff!important;border-radius:5px;font-size:14px;font-weight:800;text-decoration:none!important;box-shadow:0 7px 14px rgba(0,91,234,.24);transition:transform .2s ease,background .2s ease}\n.interdata-plan-button:hover{background:var(--blue-dark);color:#fff!important;transform:translateY(-1px)}\n@container (max-width:860px){.interdata-plan-card{flex-basis:calc(33.333% - 8px);min-width:205px}}\n@container (max-width:640px){.interdata-plan-card{flex-basis:calc(50% - 7px);min-width:215px}}\n@container (max-width:480px){.interdata-plan-carousel{padding:12px 10px}.interdata-carousel-heading{font-size:16px}.interdata-plan-card{flex-basis:86%;min-width:235px}.interdata-plan-price{font-size:31px}}\n@media (max-width:360px){.interdata-plan-card{flex-basis:90%;min-width:220px}.interdata-plan-price{font-size:29px}.interdata-plan-badge{font-size:9px}}\n<\/style>\n\n<div class=\"interdata-plan-carousel\">\n  <div class=\"interdata-carousel-heading\"><span style=\"font-family: Roboto, sans-serif; color: red;\">Si\u00eau \u01afu \u0110\u00e3i VPS \/ CLOUD SERVER - Ti\u1ebft Ki\u1ec7m \u0110\u1ebfn 70%<\/span><\/div>\n\n  <svg width=\"0\" height=\"0\" style=\"position:absolute;visibility:hidden\" aria-hidden=\"true\">\n    <symbol id=\"id-icon-cpu\" viewBox=\"0 0 24 24\"><rect x=\"7\" y=\"7\" width=\"10\" height=\"10\" rx=\"2\"><\/rect><path d=\"M4 9h3M4 15h3M17 9h3M17 15h3M9 4v3M15 4v3M9 17v3M15 17v3\"><\/path><path d=\"M10 10h4v4h-4z\"><\/path><\/symbol>\n    <symbol id=\"id-icon-ram\" viewBox=\"0 0 24 24\"><rect x=\"4\" y=\"8\" width=\"16\" height=\"8\" rx=\"2\"><\/rect><path d=\"M7 16v2M11 16v2M15 16v2M19 16v2M7 11h1M11 11h1M15 11h1\"><\/path><\/symbol>\n    <symbol id=\"id-icon-storage\" viewBox=\"0 0 24 24\"><rect x=\"6\" y=\"3\" width=\"12\" height=\"18\" rx=\"2\"><\/rect><path d=\"M9 7h6\"><\/path><circle cx=\"12\" cy=\"16\" r=\"1.5\"><\/circle><\/symbol>\n    <symbol id=\"id-icon-network\" viewBox=\"0 0 24 24\"><path d=\"M5 12.5a10 10 0 0 1 14 0\"><\/path><path d=\"M8.5 16a5 5 0 0 1 7 0\"><\/path><path d=\"M12 19h.01\"><\/path><\/symbol>\n    <symbol id=\"id-icon-gift\" viewBox=\"0 0 24 24\"><rect x=\"3\" y=\"8\" width=\"18\" height=\"13\" rx=\"2\"><\/rect><path d=\"M12 8v13M3 12h18\"><\/path><path d=\"M7.5 8C6.1 8 5 6.9 5 5.5S6.1 3 7.5 3C10 3 12 8 12 8\"><\/path><path d=\"M16.5 8C17.9 8 19 6.9 19 5.5S17.9 3 16.5 3C14 3 12 8 12 8\"><\/path><\/symbol>\n  <\/svg>\n\n  <div class=\"interdata-plan-track\">\n    <article class=\"interdata-plan-card\">\n      <h3 class=\"interdata-plan-title\">BD - Starter<\/h3>\n      <div class=\"interdata-plan-price\">699K<span>\/n\u0103m<\/span><\/div>\n      <div class=\"interdata-plan-badge\">GIA H\u1ea0N KH\u00d4NG \u0110\u1ed4I GI\u00c1<\/div>\n      <ul class=\"interdata-plan-features\">\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-cpu\"><\/use><\/svg><\/span>1 vCPU Intel Xeon<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-ram\"><\/use><\/svg><\/span>2 GB RAM<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-storage\"><\/use><\/svg><\/span>20 GB NVMe U.2<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-network\"><\/use><\/svg><\/span>Network: 100 Mbps<\/li>\n      <\/ul>\n      <div class=\"interdata-plan-spacer\"><\/div>\n      <a class=\"interdata-plan-button\" href=\"https:\/\/support.interdata.vn\/index.php?rp=\/store\/interdata-day-2026\/bd-starter\" target=\"_blank\" rel=\"nofollow sponsored noopener\">\u0110\u0103ng k\u00fd ngay<\/a>\n    <\/article>\n\n    <article class=\"interdata-plan-card\">\n      <h3 class=\"interdata-plan-title\"><span class=\"ez-toc-section\" id=\"Premium-Base-2\"><\/span>Premium Base<span class=\"ez-toc-section-end\"><\/span><\/h3>\n      <div class=\"interdata-plan-price\">999K<span>\/n\u0103m<\/span><\/div>\n      <div class=\"interdata-plan-badge\">GIA H\u1ea0N KH\u00d4NG \u0110\u1ed4I GI\u00c1<\/div>\n      <ul class=\"interdata-plan-features\">\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-cpu\"><\/use><\/svg><\/span>3 vCore Intel Xeon<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-ram\"><\/use><\/svg><\/span>3 GB RAM<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-storage\"><\/use><\/svg><\/span>30 GB SSD NVMe U.2<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-network\"><\/use><\/svg><\/span>Network: 300 Mbps<\/li>\n      <\/ul>\n      <div class=\"interdata-plan-spacer\"><\/div>\n      <a class=\"interdata-plan-button\" href=\"https:\/\/support.interdata.vn\/index.php?rp=\/store\/cyber-week-2026\/premium-base\" target=\"_blank\" rel=\"nofollow sponsored noopener\">\u0110\u0103ng k\u00fd ngay<\/a>\n    <\/article>\n\n    <article class=\"interdata-plan-card\">\n      <h3 class=\"interdata-plan-title\">BD - Personal<\/h3>\n      <div class=\"interdata-plan-price\">1.456K<span>\/n\u0103m<\/span><\/div>\n      <div class=\"interdata-plan-badge\">GIA H\u1ea0N KH\u00d4NG \u0110\u1ed4I GI\u00c1<\/div>\n      <ul class=\"interdata-plan-features\">\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-cpu\"><\/use><\/svg><\/span>2 vCPU AMD 7H12<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-ram\"><\/use><\/svg><\/span>4 GB RAM<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-storage\"><\/use><\/svg><\/span>40 GB SSD NVMe U.2<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-network\"><\/use><\/svg><\/span>Network: 300 Mbps<\/li>\n      <\/ul>\n      <div class=\"interdata-plan-spacer\"><\/div>\n      <a class=\"interdata-plan-button\" href=\"https:\/\/support.interdata.vn\/index.php?rp=\/store\/interdata-day-2026\/bd-personal\" target=\"_blank\" rel=\"nofollow sponsored noopener\">\u0110\u0103ng k\u00fd ngay<\/a>\n    <\/article>\n\n    <article class=\"interdata-plan-card\">\n      <h3 class=\"interdata-plan-title\">Cloud-Day - Base<\/h3>\n      <div class=\"interdata-plan-price\">2.666K<span>\/n\u0103m<\/span><\/div>\n      <div class=\"interdata-plan-badge\">GIA H\u1ea0N KH\u00d4NG \u0110\u1ed4I GI\u00c1<\/div>\n      <ul class=\"interdata-plan-features\">\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-gift\"><\/use><\/svg><\/span>T\u1eb7ng 80 GB S3 v\u00e0 1 N\u0102M S\u1eec D\u1ee4NG khi mua 2 n\u0103m tr\u1edf l\u00ean<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-cpu\"><\/use><\/svg><\/span>4 vCPU AMD EPYC<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-ram\"><\/use><\/svg><\/span>6 GB RAM<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-storage\"><\/use><\/svg><\/span>60 GB SSD NVMe U.2<\/li>\n        <li><span class=\"interdata-plan-icon\"><svg><use href=\"#id-icon-network\"><\/use><\/svg><\/span>Network: 10 Gbps<\/li>\n      <\/ul>\n      <div class=\"interdata-plan-spacer\"><\/div>\n      <a class=\"interdata-plan-button\" href=\"https:\/\/support.interdata.vn\/index.php?rp=\/store\/cloud-day-by-interdata-2026\/cloud-day-base\" target=\"_blank\" rel=\"nofollow sponsored noopener\">\u0110\u0103ng k\u00fd ngay<\/a>\n    <\/article>\n  <\/div>\n<\/div>\n\n\t<div id=\"gap-62173327\" class=\"gap-element clearfix\" style=\"display:block; height:auto;\">\n\t\t\n<style>\n#gap-62173327 {\n  padding-top: 30px;\n}\n<\/style>\n\t<\/div>\n\t\n","protected":false},"excerpt":{"rendered":"<p>C\u1ea5u h\u00ecnh sai \u0111\u1ecba ch\u1ec9 m\u1ea1ng khi\u1ebfn c\u00e1c m\u00e1y ch\u1ee7 n\u1ed9i b\u1ed9 m\u1ea5t k\u1ebft n\u1ed1i ho\u1eb7c v\u00f4 t\u00ecnh l\u00e0m l\u1ed9 c\u01a1 s\u1edf d\u1eef li\u1ec7u quan tr\u1ecdng ra m\u00f4i tr\u01b0\u1eddng internet c\u00f4ng c\u1ed9ng l\u00e0 l\u1ed7i b\u1ea3o m\u1eadt kinh \u0111i\u1ec3n c\u1ee7a nhi\u1ec1u qu\u1ea3n tr\u1ecb vi\u00ean. Vi\u1ec7c hi\u1ec3u r\u00f5 b\u1ea3n ch\u1ea5t c\u1ee7a subnet mask gi\u00fap b\u1ea1n ph\u00e2n ranh<\/p>\n","protected":false},"author":2,"featured_media":41844,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[83],"tags":[],"class_list":["post-41842","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bao-mat-an-ninh-mang"],"_links":{"self":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/41842","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/comments?post=41842"}],"version-history":[{"count":3,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/41842\/revisions"}],"predecessor-version":[{"id":41846,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/41842\/revisions\/41846"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/media\/41844"}],"wp:attachment":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/media?parent=41842"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/categories?post=41842"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/tags?post=41842"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}