{"id":116023,"date":"2025-06-23T16:31:04","date_gmt":"2025-06-23T09:31:04","guid":{"rendered":"https:\/\/tino.vn\/blog\/?p=116023"},"modified":"2026-10-28T11:40:21","modified_gmt":"2026-10-28T04:40:21","slug":"subdomain-la-gi","status":"publish","type":"post","link":"https:\/\/tino.vn\/blog\/subdomain-la-gi\/","title":{"rendered":"Subdomain l\u00e0 g\u00ec? Kh\u00e1c g\u00ec t\u00ean mi\u1ec1n ch\u00ednh v\u00e0 th\u01b0 m\u1ee5c con"},"content":{"rendered":"\n

Subdomain (t\u00ean mi\u1ec1n ph\u1ee5) l\u00e0 ph\u1ea7n t\u00ean \u0111\u1ee9ng tr\u01b0\u1edbc t\u00ean mi\u1ec1n ch\u00ednh v\u00e0 ng\u0103n c\u00e1ch b\u1eb1ng d\u1ea5u ch\u1ea5m, v\u00ed d\u1ee5 blog.example.vn<\/code> l\u00e0 subdomain c\u1ee7a example.vn<\/code>. Subdomain \u0111\u01b0\u1ee3c t\u1ea1o b\u1eb1ng b\u1ea3n ghi DNS trong v\u00f9ng c\u1ee7a t\u00ean mi\u1ec1n ch\u00ednh, kh\u00f4ng ph\u1ea3i \u0111\u0103ng k\u00fd hay tr\u1ea3 ph\u00ed ri\u00eang, v\u00e0 c\u00f3 th\u1ec3 ch\u1ea1y m\u1ed9t website kh\u00e1c h\u1eb3n website ch\u00ednh.<\/strong><\/p>\n\n\n\n

T\u00ean mi\u1ec1n ch\u00ednh l\u00e0 \u0111\u1ecba ch\u1ec9 b\u1ea1n \u0111\u0103ng k\u00fd v\u00e0 tr\u1ea3 ph\u00ed duy tr\u00ec h\u1eb1ng n\u0103m (t\u00ean mi\u1ec1n l\u00e0 g\u00ec<\/a>); subdomain l\u00e0 nh\u00e1nh do ch\u1ee7 t\u00ean mi\u1ec1n t\u1ef1 t\u1ea1o th\u00eam. V\u00ec subdomain ch\u1ec9 t\u1ed3n t\u1ea1i nh\u1edd b\u1ea3n ghi trong DNS<\/a>, b\u00e0i n\u00e0y \u0111i t\u1eeb c\u1ea5u tr\u00fac, c\u00e1ch ph\u00e2n gi\u1ea3i \u0111\u1ebfn l\u00fac n\u00ean ch\u1ecdn subdomain hay th\u01b0 m\u1ee5c con.<\/p>\n\n\n\n

Subdomain l\u00e0 g\u00ec?<\/h2>\n\n\n\n

Subdomain l\u00e0 m\u1ed9t t\u00ean n\u1eb1m d\u01b0\u1edbi t\u00ean mi\u1ec1n ch\u00ednh trong c\u00e2y t\u00ean mi\u1ec1n, d\u00f9ng \u0111\u1ec3 t\u00e1ch m\u1ed9t ph\u1ea7n website ho\u1eb7c m\u1ed9t d\u1ecbch v\u1ee5 ri\u00eang nh\u01b0 blog, c\u1eeda h\u00e0ng, trang h\u1ed7 tr\u1ee3, m\u00f4i tr\u01b0\u1eddng th\u1eed nghi\u1ec7m. Ch\u1ee7 t\u00ean mi\u1ec1n t\u1ea1o bao nhi\u00eau subdomain tu\u1ef3 \u00fd, m\u1ed7i subdomain c\u00f3 th\u1ec3 tr\u1ecf v\u1ec1 m\u00e1y ch\u1ee7 kh\u00e1c v\u00e0 c\u00f3 n\u1ed9i dung ri\u00eang.<\/p>\n\n\n\n

V\u00ed d\u1ee5 th\u01b0\u1eddng g\u1eb7p: shop.example.vn<\/code> cho c\u1eeda h\u00e0ng, support.example.vn<\/code> cho trung t\u00e2m h\u1ed7 tr\u1ee3, dev.example.vn<\/code> cho b\u1ea3n th\u1eed nghi\u1ec7m. B\u1ea3n th\u00e2n www.example.vn<\/code> v\u1ec1 k\u1ef9 thu\u1eadt c\u0169ng l\u00e0 m\u1ed9t subdomain, ch\u1ec9 l\u00e0 \u0111\u01b0\u1ee3c quy \u01b0\u1edbc d\u00f9ng cho website ch\u00ednh.<\/p>\n\n\n\n

C\u1ea5u tr\u00fac c\u1ee7a subdomain trong URL<\/h3>\n\n\n\n

M\u1ed9t t\u00ean mi\u1ec1n \u0111\u1ecdc t\u1eeb ph\u1ea3i sang tr\u00e1i: \u0111u\u00f4i t\u00ean mi\u1ec1n (TLD), r\u1ed3i t\u00ean mi\u1ec1n c\u1ea5p hai, r\u1ed3i t\u1edbi subdomain \u1edf ngo\u00e0i c\u00f9ng b\u00ean tr\u00e1i. Trong blog.yourdomain.com<\/code>, .com<\/code> l\u00e0 TLD, yourdomain<\/code> l\u00e0 t\u00ean mi\u1ec1n c\u1ea5p hai, blog<\/code> l\u00e0 subdomain.<\/p>\n\n\n\n

\"S\u01a1
\u201cRoot Domain Name\u201d trong \u1ea3nh l\u00e0 c\u00e1ch g\u1ecdi quen thu\u1ed9c c\u1ee7a t\u00ean mi\u1ec1n ch\u00ednh; trong DNS, g\u1ed1c (root) th\u1eadt s\u1ef1 l\u00e0 d\u1ea5u ch\u1ea5m cu\u1ed1i c\u1ee7a t\u00ean.<\/figcaption><\/figure>\n\n\n\n

Subdomain c\u00f3 th\u1ec3 nhi\u1ec1u c\u1ea5p, v\u00ed d\u1ee5 api.dev.example.vn<\/code>. Theo RFC 1035<\/a>, m\u1ed7i nh\u00e3n gi\u1eefa hai d\u1ea5u ch\u1ea5m d\u00e0i t\u1ed1i \u0111a 63 k\u00fd t\u1ef1 v\u00e0 c\u1ea3 t\u00ean d\u00e0i t\u1ed1i \u0111a 255 octet, n\u00ean s\u1ed1 subdomain kh\u00f4ng b\u1ecb gi\u1edbi h\u1ea1n b\u1edfi DNS m\u00e0 b\u1edfi b\u1ea3ng \u0111i\u1ec1u khi\u1ec3n hosting ho\u1eb7c n\u01a1i qu\u1ea3n l\u00fd DNS. Xem th\u00eam FQDN l\u00e0 g\u00ec<\/a> v\u00e0 \u0111u\u00f4i t\u00ean mi\u1ec1n (TLD)<\/a>.<\/p>\n\n\n\n

Subdomain kh\u00e1c t\u00ean mi\u1ec1n ch\u00ednh nh\u01b0 th\u1ebf n\u00e0o?<\/h2>\n\n\n\n

T\u00ean mi\u1ec1n ch\u00ednh ph\u1ea3i \u0111\u0103ng k\u00fd t\u1ea1i nh\u00e0 \u0111\u0103ng k\u00fd v\u00e0 gia h\u1ea1n h\u1eb1ng n\u0103m, c\u00f2n subdomain do ch\u1ee7 t\u00ean mi\u1ec1n t\u1ef1 t\u1ea1o trong trang qu\u1ea3n l\u00fd DNS, kh\u00f4ng ph\u00e1t sinh ph\u00ed \u0111\u0103ng k\u00fd. Subdomain ph\u1ee5 thu\u1ed9c ho\u00e0n to\u00e0n v\u00e0o t\u00ean mi\u1ec1n ch\u00ednh: t\u00ean mi\u1ec1n ch\u00ednh h\u1ebft h\u1ea1n th\u00ec m\u1ecdi subdomain c\u0169ng ng\u1eebng ph\u00e2n gi\u1ea3i.<\/p>\n\n\n\n

Ti\u00eau ch\u00ed<\/th>T\u00ean mi\u1ec1n ch\u00ednh<\/th>Subdomain<\/th><\/tr><\/thead>
V\u00ed d\u1ee5<\/td>example.vn<\/code><\/td>blog.example.vn<\/code>, shop.example.vn<\/code><\/td><\/tr>
C\u00e1ch c\u00f3<\/td>\u0110\u0103ng k\u00fd t\u1ea1i nh\u00e0 \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n<\/td>Th\u00eam b\u1ea3n ghi DNS (A, AAAA ho\u1eb7c CNAME) trong v\u00f9ng c\u1ee7a t\u00ean mi\u1ec1n ch\u00ednh<\/td><\/tr>
Chi ph\u00ed<\/td>Ph\u00ed \u0111\u0103ng k\u00fd v\u00e0 duy tr\u00ec h\u1eb1ng n\u0103m<\/td>Kh\u00f4ng c\u00f3 ph\u00ed \u0111\u0103ng k\u00fd ri\u00eang<\/td><\/tr>
Quy\u1ec1n s\u1edf h\u1eefu<\/td>Ghi nh\u1eadn trong d\u1eef li\u1ec7u WHOIS\/RDAP<\/td>Thu\u1ed9c ng\u01b0\u1eddi gi\u1eef t\u00ean mi\u1ec1n ch\u00ednh<\/td><\/tr>
Khi t\u00ean mi\u1ec1n ch\u00ednh h\u1ebft h\u1ea1n<\/td>Ng\u1eebng ho\u1ea1t \u0111\u1ed9ng<\/td>Ng\u1eebng ho\u1ea1t \u0111\u1ed9ng theo<\/td><\/tr>
M\u00e1y ch\u1ee7<\/td>M\u1ed9t ho\u1eb7c nhi\u1ec1u<\/td>C\u00f3 th\u1ec3 kh\u00e1c m\u00e1y ch\u1ee7 c\u1ee7a t\u00ean mi\u1ec1n ch\u00ednh<\/td><\/tr><\/tbody><\/table>
T\u00ean mi\u1ec1n ch\u00ednh v\u00e0 subdomain (t\u1ed5ng h\u1ee3p 27\/10\/2026)<\/figcaption><\/figure>\n\n\n\n

Subdomain ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o?<\/h2>\n\n\n\n

Subdomain ho\u1ea1t \u0111\u1ed9ng nh\u1edd hai b\u01b0\u1edbc: DNS tr\u1ea3 \u0111\u1ecba ch\u1ec9 IP cho \u0111\u00fang t\u00ean subdomain, r\u1ed3i web server \u0111\u1ecdc t\u00ean trong y\u00eau c\u1ea7u (tr\u01b0\u1eddng Host) \u0111\u1ec3 ch\u1ecdn th\u01b0 m\u1ee5c website t\u01b0\u01a1ng \u1ee9ng. V\u00ec c\u00f3 b\u1ea3n ghi DNS ri\u00eang, subdomain c\u00f3 th\u1ec3 tr\u1ecf sang m\u00e1y ch\u1ee7 kh\u00e1c h\u1eb3n website ch\u00ednh; th\u01b0 m\u1ee5c con th\u00ec lu\u00f4n d\u00f9ng chung m\u00e1y ch\u1ee7.<\/p>\n\n\n\n

\"S\u01a1<\/figure>\n\n\n\n