{"id":12356538,"date":"2026-03-09T17:58:12","date_gmt":"2026-03-09T09:58:12","guid":{"rendered":"https:\/\/www.likacloud.com\/knowledge\/%e5%9f%9f%e5%90%8d%e8%a7%a3%e6%9e%90%e5%85%a8%e6%94%bb%e7%95%a5%ef%bc%9a%e4%bb%8e%e8%b4%ad%e4%b9%b0%e8%a7%a3%e6%9e%90%e5%88%b0%e9%ab%98%e9%80%9f%e8%ae%bf%e9%97%ae%e7%9a%84%e5%ae%8c%e6%95%b4%e6%8c%87\/"},"modified":"2026-03-11T14:28:45","modified_gmt":"2026-03-11T06:28:45","slug":"domain-dns-resolution-guide-from-purchase-to-fast-access","status":"publish","type":"knowledge_post","link":"https:\/\/www.likacloud.com\/vi\/knowledge\/domain\/domain-dns-resolution-guide-from-purchase-to-fast-access\/","title":{"rendered":"H\u01b0\u1edbng d\u1eabn to\u00e0n di\u1ec7n v\u1ec1 ph\u00e2n gi\u1ea3i t\u00ean mi\u1ec1n: T\u1eeb mua t\u00ean mi\u1ec1n \u0111\u1ebfn truy c\u1eadp t\u1ed1c \u0111\u1ed9 cao"},"content":{"rendered":"

Hi\u1ec3u v\u1ec1 t\u00ean mi\u1ec1n v\u00e0 h\u1ec7 th\u1ed1ng gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n (DNS)<\/h2>\n\n\n\n

Khi b\u1ea1n truy c\u1eadp m\u1ed9t trang web, b\u1ea1n nh\u1eadp t\u00ean mi\u1ec1n nh\u01b0 \u201cexample.com\u201d v\u00e0o tr\u00ecnh duy\u1ec7t. Tuy nhi\u00ean, khi c\u00e1c m\u00e1y t\u00ednh v\u00e0 thi\u1ebft b\u1ecb m\u1ea1ng giao ti\u1ebfp v\u1edbi nhau tr\u00ean Internet, ch\u00fang s\u1eed d\u1ee5ng \u0111\u1ecba ch\u1ec9 IP (IP address) \u0111\u01b0\u1ee3c t\u1ea1o th\u00e0nh t\u1eeb c\u00e1c con s\u1ed1 (v\u00ed d\u1ee5: 192.0.2.1). Qu\u00e1 tr\u00ecnh gi\u1ea3i \u0111\u1ecbnh t\u00ean mi\u1ec1n (Domain Name System \u2013 DNS) ch\u00ednh l\u00e0 \u201cs\u1ed5 \u0111i\u1ec7n tho\u1ea1i Internet\u201d ho\u1eb7c \u201cng\u01b0\u1eddi d\u1ecbch\u201d gi\u00fap k\u1ebft n\u1ed1i hai th\u1ee9 n\u00e0y l\u1ea1i v\u1edbi nhau.<\/p>\n\n\n\n

Ch\u1ee9c n\u0103ng c\u1ed1t l\u00f5i c\u1ee7a n\u00f3 l\u00e0 chuy\u1ec3n \u0111\u1ed5i c\u00e1c t\u00ean mi\u1ec1n d\u1ec5 nh\u1edb \u0111\u1ed1i v\u1edbi con ng\u01b0\u1eddi th\u00e0nh \u0111\u1ecba ch\u1ec9 IP d\u1ec5 x\u1eed l\u00fd b\u1edfi m\u00e1y t\u00ednh. Qu\u00e1 tr\u00ecnh n\u00e0y \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 truy v\u1ea5n DNS (DNS Lookup). To\u00e0n b\u1ed9 h\u1ec7 th\u1ed1ng DNS l\u00e0 m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u ph\u00e2n t\u00e1n tr\u00ean to\u00e0n c\u1ea7u, \u0111\u01b0\u1ee3c t\u1ed5 ch\u1ee9c theo c\u1ea5u tr\u00fac c\u00e2y c\u00f3 c\u1ea5p \u0111\u1ed9. N\u00f3 b\u1eaft \u0111\u1ea7u t\u1eeb t\u00ean mi\u1ec1n g\u1ed1c (.), sau \u0111\u00f3 ti\u1ebfp t\u1ee5c ph\u00e2n nh\u00e1nh xu\u1ed1ng c\u00e1c t\u00ean mi\u1ec1n c\u1ea5p cao nh\u01b0.com, .org, c\u00e1c t\u00ean mi\u1ec1n c\u1ea5p hai nh\u01b0 example.com, v\u00e0 c\u00e1c t\u00ean mi\u1ec1n con \u1edf c\u1ea5p \u0111\u1ed9 s\u00e2u h\u01a1n n\u1eefa.<\/p>\n\n\n\n

M\u1ed9t th\u00e0nh ph\u1ea7n quan tr\u1ecdng c\u1ee7a H\u1ec7 th\u1ed1ng T\u00ean mi\u1ec1n (Domain Name System \u2013 DNS)<\/h3>\n\n\n\n

\u57df\u540d\u7cfb\u7edf\u4e3b\u8981\u7531\u51e0\u4e2a\u6838\u5fc3\u90e8\u5206\u7ec4\u6210\u3002\u9996\u5148\u662f\u57df\u540d\u670d\u52a1\u5668\uff08Name Server\uff09\uff0c\u5b83\u662f\u5b58\u50a8\u57df\u540d\u4e0eIP\u5730\u5740\u6620\u5c04\u5173\u7cfb\u7684\u670d\u52a1\u5668\uff0c\u662f\u5904\u7406\u67e5\u8be2\u8bf7\u6c42\u7684\u5173\u952e\u3002\u5176\u6b21\u662f\u57df\u540d\u8bb0\u5f55\uff08DNS Record\uff09\uff0c\u8fd9\u4e9b\u8bb0\u5f55\u5b58\u50a8\u5728\u57df\u540d\u670d\u52a1\u5668\u4e2d\uff0c\u6bcf\u4e00\u79cd\u8bb0\u5f55\u7c7b\u578b\u90fd\u6709\u7279\u5b9a\u7528\u9014\u3002\u6700\u540e\u662f\u89e3\u6790\u5668\uff08Resolver\uff09\uff0c\u901a\u5e38\u7531\u4f60\u7684\u4e92\u8054\u7f51\u670d\u52a1\u63d0\u4f9b\u5546\uff08ISP\uff09\u6216\u516c\u5171DNS\u670d\u52a1\uff08\u5982Google Public DNS\uff09\u63d0\u4f9b\uff0c\u5b83\u7684\u804c\u8d23\u662f\u63a5\u6536\u7528\u6237\u7684\u67e5\u8be2\u8bf7\u6c42\uff0c\u5e76\u5728\u6574\u4e2aDNS\u7cfb\u7edf\u4e2d\u5bfb\u627e\u7b54\u6848\u3002<\/p>\n\n\n\n

Chuy\u1ebfn kh\u00e1m ph\u00e1 \u201ch\u1eadu tr\u01b0\u1eddng\u201d c\u1ee7a qu\u00e1 tr\u00ecnh ph\u00e2n t\u00edch d\u1eef li\u1ec7u<\/h3>\n\n\n\n

Qu\u00e1 tr\u00ecnh gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n m\u1ed9t c\u00e1ch \u0111\u1ea7y \u0111\u1ee7 ph\u1ee9c t\u1ea1p h\u01a1n nhi\u1ec1u so v\u1edbi b\u1ea1n t\u01b0\u1edfng t\u01b0\u1ee3ng. Khi b\u1ea1n nh\u1eadp m\u1ed9t \u0111\u1ecba ch\u1ec9 v\u00e0o tr\u00ecnh duy\u1ec7t, m\u00e1y t\u00ednh c\u1ee7a b\u1ea1n s\u1ebd tr\u01b0\u1edbc ti\u00ean ki\u1ec3m tra b\u1ed9 nh\u1edb \u0111\u1ec7m DNS c\u1ee5c b\u1ed9 \u0111\u1ec3 xem li\u1ec7u c\u00f3 b\u1ea3n ghi n\u00e0o li\u00ean quan \u0111\u1ebfn \u0111\u1ecba ch\u1ec9 \u0111\u00f3 hay kh\u00f4ng. N\u1ebfu kh\u00f4ng t\u00ecm th\u1ea5y, y\u00eau c\u1ea7u s\u1ebd \u0111\u01b0\u1ee3c g\u1eedi \u0111\u1ebfn b\u1ed9 gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n (recursive resolver). B\u1ed9 gi\u1ea3i quy\u1ebft n\u00e0y s\u1ebd b\u1eaft \u0111\u1ea7u qu\u00e1 tr\u00ecnh t\u00ecm ki\u1ebfm t\u1eeb m\u00e1y ch\u1ee7 DNS g\u1ed1c, sau \u0111\u00f3 l\u1ea7n l\u01b0\u1ee3t li\u00ean h\u1ec7 v\u1edbi c\u00e1c m\u00e1y ch\u1ee7 t\u00ean mi\u1ec1n c\u1ea5p cao nh\u1ea5t (top-level domain servers) v\u00e0 c\u00e1c m\u00e1y ch\u1ee7 t\u00ean mi\u1ec1n c\u00f3 th\u1ea9m quy\u1ec1n (authoritative domain servers) \u0111\u1ec3 thu th\u1eadp \u0111\u1ecba ch\u1ec9 IP t\u01b0\u01a1ng \u1ee9ng v\u1edbi t\u00ean mi\u1ec1n m\u1ee5c ti\u00eau. Qu\u00e1 tr\u00ecnh n\u00e0y th\u01b0\u1eddng ch\u1ec9 m\u1ea5t v\u00e0i tr\u0103m mili gi\u00e2y, nh\u01b0ng l\u1ea1i r\u1ea5t quan tr\u1ecdng \u0111\u1ed1i v\u1edbi hi\u1ec7u su\u1ea5t m\u1ea1ng.<\/p>\n\n\n\n

Chi ti\u1ebft v\u1ec1 vi\u1ec7c mua t\u00ean mi\u1ec1n v\u00e0 c\u1ea5u h\u00ecnh c\u01a1 b\u1ea3n<\/h2>\n\n\n\n

Tr\u01b0\u1edbc khi b\u1eaft \u0111\u1ea7u qu\u00e1 tr\u00ecnh gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n (domain name resolution), b\u1ea1n c\u1ea7n ph\u1ea3i s\u1edf h\u1eefu m\u1ed9t t\u00ean mi\u1ec1n. Vi\u1ec7c ch\u1ecdn m\u1ed9t t\u00ean mi\u1ec1n ph\u00f9 h\u1ee3p ch\u00ednh l\u00e0 b\u01b0\u1edbc \u0111\u1ea7u ti\u00ean trong h\u00e0nh tr\u00ecnh x\u00e2y d\u1ef1ng danh t\u00ednh tr\u1ef1c tuy\u1ebfn c\u1ee7a b\u1ea1n.<\/p>\n\n\n

\n\n
\n \u0110\u0103ng k\u00fd t\u00ean mi\u1ec1n hosting.com<\/strong>\n
Th\u00f4ng qua g\u00f3i l\u01b0u tr\u1eef chia s\u1ebb h\u00e0ng n\u0103m, nh\u1eadn t\u00ean mi\u1ec1n .com mi\u1ec5n ph\u00ed trong m\u1ed9t n\u0103m, h\u1ed7 tr\u1ee3 300+ h\u1eadu t\u1ed1 t\u00ean mi\u1ec1n, qu\u1ea3n l\u00fd DNS mi\u1ec5n ph\u00ed, h\u1ed7 tr\u1ee3 kh\u00e1ch h\u00e0ng 24\/7<\/div>\n <\/div>\n\n
\n \n \n \"\u0110\u0103ng\n \n \n <\/a>\n \n \n Truy c\u1eadp hosting.com <\/a>\n <\/div>\n <\/div>\n\n \n\n\n\n\n\n\n

L\u00e0m th\u1ebf n\u00e0o \u0111\u1ec3 ch\u1ecdn v\u00e0 \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n?<\/h3>\n\n\n\n

Khi ch\u1ecdn t\u00ean mi\u1ec1n, b\u1ea1n n\u00ean tu\u00e2n theo c\u00e1c nguy\u00ean t\u1eafc sau: d\u1ec5 nh\u1edb, ng\u1eafn g\u1ecdn, li\u00ean quan \u0111\u1ebfn th\u01b0\u01a1ng hi\u1ec7u ho\u1eb7c n\u1ed9i dung, v\u00e0 tr\u00e1nh s\u1eed d\u1ee5ng k\u1ebft h\u1ee3p ch\u1eef c\u00e1i v\u1edbi s\u1ed1. Vi\u1ec7c \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n c\u1ea7n \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n th\u00f4ng qua c\u00e1c nh\u00e0 cung c\u1ea5p d\u1ecbch v\u1ee5 \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n \u0111\u01b0\u1ee3c ICANN ch\u1ee9ng nh\u1eadn, nh\u01b0 Alibaba Cloud, Tencent Cloud, GoDaddy ho\u1eb7c Namecheap. Trong qu\u00e1 tr\u00ecnh \u0111\u0103ng k\u00fd, b\u1ea1n c\u1ea7n cung c\u1ea5p th\u00f4ng tin li\u00ean l\u1ea1c h\u1ee3p l\u1ec7 v\u00e0 ch\u00ednh x\u00e1c, v\u00e0 th\u01b0\u1eddng ph\u1ea3i thanh to\u00e1n ph\u00ed \u0111\u0103ng k\u00fd theo n\u0103m. Ngo\u00e0i ra, b\u1ea1n n\u00ean ch\u00fa \u00fd \u0111\u1ebfn c\u00e1c d\u1ecbch v\u1ee5 b\u1ea3o v\u1ec7 quy\u1ec1n ri\u00eang t\u01b0 cho t\u00ean mi\u1ec1n \u0111\u1ec3 tr\u00e1nh vi\u1ec7c th\u00f4ng tin c\u00e1 nh\u00e2n c\u1ee7a b\u1ea1n b\u1ecb c\u00f4ng khai trong c\u01a1 s\u1edf d\u1eef li\u1ec7u WHOIS.<\/p>\n\n\n\n

C\u00e0i \u0111\u1eb7t c\u00e1c m\u00e1y ch\u1ee7 t\u00ean (Name Servers) c\u00f3 th\u1ea9m quy\u1ec1n<\/h3>\n\n\n\n

Sau khi \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n, b\u01b0\u1edbc quan tr\u1ecdng nh\u1ea5t l\u00e0 thi\u1ebft l\u1eadp m\u00e1y ch\u1ee7 \u0111\u1ecbnh danh c\u00f3 th\u1ea9m quy\u1ec1n cho t\u00ean mi\u1ec1n. B\u01b0\u1edbc n\u00e0y x\u00e1c \u0111\u1ecbnh ai s\u1ebd \u201cqu\u1ea3n l\u00fd\u201d b\u1ea3n ghi DNS c\u1ee7a t\u00ean mi\u1ec1n c\u1ee7a b\u1ea1n. Th\u00f4ng th\u01b0\u1eddng, b\u1ea1n c\u00f3 hai l\u1ef1a ch\u1ecdn: m\u1ed9t l\u00e0 s\u1eed d\u1ee5ng m\u00e1y ch\u1ee7 DNS mi\u1ec5n ph\u00ed do nh\u00e0 \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n cung c\u1ea5p; hai l\u00e0 s\u1eed d\u1ee5ng d\u1ecbch v\u1ee5 DNS chuy\u00ean nghi\u1ec7p c\u1ee7a b\u00ean th\u1ee9 ba, nh\u01b0 Cloudflare, AWS Route 53 ho\u1eb7c DNSPod, ch\u00fang th\u01b0\u1eddng c\u00f3 \u01b0u th\u1ebf h\u01a1n v\u1ec1 hi\u1ec7u su\u1ea5t, b\u1ea3o m\u1eadt v\u00e0 t\u00ednh n\u0103ng. Ph\u01b0\u01a1ng ph\u00e1p thi\u1ebft l\u1eadp l\u00e0 trong b\u1ea3ng qu\u1ea3n l\u00fd c\u1ee7a nh\u00e0 \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n, b\u1ea1n s\u1eeda \u0111\u1ed5i b\u1ea3n ghi NS m\u1eb7c \u0111\u1ecbnh th\u00e0nh \u0111\u1ecba ch\u1ec9 m\u00e1y ch\u1ee7 NS c\u1ee7a d\u1ecbch v\u1ee5 b\u1ea1n ch\u1ecdn, ch\u1eb3ng h\u1ea1n nh\u01b0 ns1.cloudflare.com v\u00e0 ns2.cloudflare.com.<\/p>\n\n\n\n

Hi\u1ec3u r\u00f5 c\u00e1c lo\u1ea1i b\u1ea3n ghi DNS quan tr\u1ecdng<\/h3>\n\n\n\n

Trong b\u1ea3ng \u0111i\u1ec1u khi\u1ec3n c\u1ee7a m\u00e1y ch\u1ee7 t\u00ean mi\u1ec1n (Domain Name Server \u2013 DNS), b\u1ea1n s\u1ebd c\u1ea5u h\u00ecnh c\u00e1c lo\u1ea1i b\u1ea3n ghi DNS kh\u00e1c nhau. B\u1ea3n ghi A l\u00e0 lo\u1ea1i b\u1ea3n ghi c\u01a1 b\u1ea3n nh\u1ea5t; n\u00f3 li\u00ean k\u1ebft t\u00ean mi\u1ec1n tr\u1ef1c ti\u1ebfp v\u1edbi m\u1ed9t \u0111\u1ecba ch\u1ec9 IPv4. B\u1ea3n ghi AAAA t\u01b0\u01a1ng t\u1ef1 nh\u01b0 b\u1ea3n ghi A, nh\u01b0ng n\u00f3 li\u00ean k\u1ebft t\u00ean mi\u1ec1n v\u1edbi m\u1ed9t \u0111\u1ecba ch\u1ec9 IPv6. B\u1ea3n ghi CNAME (Canonical Name Record) \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111\u1eb7t t\u00ean mi\u1ec1n n\u00e0y l\u00e0m t\u00ean g\u1ecdi kh\u00e1c cho m\u1ed9t t\u00ean mi\u1ec1n kh\u00e1c, thay v\u00ec \u0111\u1ecba ch\u1ec9 IP; v\u00ed d\u1ee5 ph\u1ed5 bi\u1ebfn l\u00e0 s\u1eed d\u1ee5ng www.example.com \u0111\u1ec3 tr\u1ecf \u0111\u1ebfn example.com. B\u1ea3n ghi MX (Mail Exchange Record) \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf ri\u00eang \u0111\u1ec3 ch\u1ec9 \u0111\u1ecbnh \u0111\u1ecba ch\u1ec9 m\u00e1y ch\u1ee7 email nh\u1eadn th\u01b0 cho t\u00ean mi\u1ec1n \u0111\u00f3. B\u1ea3n ghi TXT (Text Record) d\u00f9ng \u0111\u1ec3 l\u01b0u tr\u1eef th\u00f4ng tin v\u0103n b\u1ea3n t\u00f9y \u00fd; m\u1ee5c \u0111\u00edch ph\u1ed5 bi\u1ebfn nh\u1ea5t c\u1ee7a n\u00f3 l\u00e0 x\u00e1c th\u1ef1c quy\u1ec1n s\u1edf h\u1eefu t\u00ean mi\u1ec1n (\u0111\u1ed1i v\u1edbi c\u00e1c c\u00f4ng c\u1ee5 t\u00ecm ki\u1ebfm, d\u1ecbch v\u1ee5 email) v\u00e0 c\u1ea5u h\u00ecnh c\u00e1c ch\u00ednh s\u00e1ch b\u1ea3o m\u1eadt email nh\u01b0 SPF (Sender Policy Framework) ho\u1eb7c DKIM (DomainKeys Identified Mail).<\/p>\n\n\n\n

Chi\u1ebfn l\u01b0\u1ee3c ph\u00e2n t\u00edch n\u00e2ng cao v\u00e0 t\u1ed1i \u01b0u h\u00f3a hi\u1ec7u su\u1ea5t<\/h2>\n\n\n\n

Sau khi ho\u00e0n th\u00e0nh c\u00e1c c\u1ea5u h\u00ecnh ph\u00e2n t\u00edch c\u01a1 b\u1ea3n, b\u1ea1n c\u00f3 th\u1ec3 n\u00e2ng cao th\u00eam \u0111\u1ed9 tin c\u1eady, b\u1ea3o m\u1eadt v\u00e0 t\u1ed1c \u0111\u1ed9 truy c\u1eadp c\u1ee7a trang web b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng c\u00e1c chi\u1ebfn l\u01b0\u1ee3c n\u00e2ng cao.<\/p>\n\n\n\n

C\u00e2n b\u1eb1ng t\u1ea3i v\u00e0 chuy\u1ec3n \u0111\u1ed5i d\u1ef1 ph\u00f2ng<\/h3>\n\n\n\n

B\u1ea1n c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng DNS \u0111\u1ec3 th\u1ef1c hi\u1ec7n vi\u1ec7c ph\u00e2n b\u1ed5 t\u1ea3i (load balancing) m\u1ed9t c\u00e1ch \u0111\u01a1n gi\u1ea3n. V\u00ed d\u1ee5, b\u1ea1n c\u00f3 th\u1ec3 th\u00eam nhi\u1ec1u b\u1ea3n ghi lo\u1ea1i A (A record) cho c\u00f9ng m\u1ed9t t\u00ean m\u00e1y ch\u1ee7 (ch\u1eb3ng h\u1ea1n l\u00e0 www) v\u00e0 ch\u1ec9 \u0111\u1ecbnh c\u00e1c \u0111\u1ecba ch\u1ec9 IP c\u1ee7a nhi\u1ec1u m\u00e1y ch\u1ee7 kh\u00e1c nhau. Tr\u00ecnh gi\u1ea3i m\u00e3 DNS s\u1ebd tr\u1ea3 v\u1ec1 c\u00e1c \u0111\u1ecba ch\u1ec9 IP n\u00e0y theo th\u1ee9 t\u1ef1 lu\u00e2n phi\u00ean, t\u1eeb \u0111\u00f3 ph\u00e2n ph\u1ed1i l\u01b0u l\u01b0\u1ee3ng truy c\u1eadp \u0111\u1ebfn c\u00e1c m\u00e1y ch\u1ee7 kh\u00e1c nhau, gi\u00fap gi\u1ea3m b\u1edbt \u00e1p l\u1ef1c l\u00ean t\u1eebng m\u00e1y ch\u1ee7.<\/p>\n\n\n\n

C\u00e1ch ti\u1ebfp c\u1eadn n\u00e2ng cao h\u01a1n l\u00e0 s\u1eed d\u1ee5ng c\u01a1 ch\u1ebf chuy\u1ec3n ti\u1ebfp d\u1ecbch v\u1ee5 d\u1ef1a tr\u00ean c\u00e1c b\u00e0i ki\u1ec3m tra t\u00ecnh tr\u1ea1ng s\u1ee9c kh\u1ecfe (health checks) c\u1ee7a h\u1ec7 th\u1ed1ng. M\u1ed9t s\u1ed1 d\u1ecbch v\u1ee5 DNS th\u00f4ng minh (nh\u01b0 AWS Route 53, Cloudflare) c\u00f3 th\u1ec3 theo d\u00f5i li\u00ean t\u1ee5c t\u00ecnh tr\u1ea1ng ho\u1ea1t \u0111\u1ed9ng c\u1ee7a c\u00e1c m\u00e1y ch\u1ee7 ph\u00eda sau (backend servers). Khi IP c\u1ee7a m\u00e1y ch\u1ee7 ch\u00ednh b\u1ecb ph\u00e1t hi\u1ec7n l\u00e0 kh\u00f4ng ho\u1ea1t \u0111\u1ed9ng (down), DNS s\u1ebd t\u1ef1 \u0111\u1ed9ng chuy\u1ec3n h\u01b0\u1edbng truy c\u1eadp \u0111\u1ebfn IP c\u1ee7a m\u00e1y ch\u1ee7 d\u1ef1 ph\u00f2ng \u0111ang ho\u1ea1t \u0111\u1ed9ng b\u00ecnh th\u01b0\u1eddng, gi\u00fap \u0111\u1ea3m b\u1ea3o t\u00ednh kh\u1ea3 d\u1ee5ng cao (high availability) c\u1ee7a d\u1ecbch v\u1ee5. Qu\u00e1 tr\u00ecnh n\u00e0y g\u1ea7n nh\u01b0 kh\u00f4ng g\u00e2y \u1ea3nh h\u01b0\u1edfng g\u00ec \u0111\u1ebfn ng\u01b0\u1eddi d\u00f9ng.<\/p>\n\n\n\n

S\u1eed d\u1ee5ng DNS Prefetching v\u00e0 CDN \u0111\u1ec3 t\u0103ng t\u1ed1c truy c\u1eadp web<\/h3>\n\n\n\n

DNS\u9884\u83b7\u53d6\uff08DNS Prefetching\uff09\u662f\u4e00\u79cd\u524d\u7aef\u6d4f\u89c8\u5668\u4f18\u5316\u6280\u672f\u3002\u901a\u8fc7\u5728\u7f51\u9875HTML\u7684 `<head>` \u90e8\u5206\u6dfb\u52a0 `<link rel=\u201ddns-prefetch\u201d href=\u201d\/\/cdn.example.com\u201d>` \u8fd9\u6837\u7684\u6807\u7b7e\uff0c\u53ef\u4ee5\u63d0\u793a\u6d4f\u89c8\u5668\u5728\u52a0\u8f7d\u9875\u9762\u4e3b\u4f53\u5185\u5bb9\u4e4b\u524d\uff0c\u63d0\u524d\u89e3\u6790\u540e\u7eed\u53ef\u80fd\u7528\u5230\u7684\u57df\u540d\uff08\u5982CDN\u3001\u7b2c\u4e09\u65b9API\u7684\u57df\u540d\uff09\uff0c\u4ece\u800c\u51cf\u5c11\u540e\u7eed\u8d44\u6e90\u7684\u7b49\u5f85\u65f6\u95f4\u3002<\/p>\n\n\n\n

B\u1ea3n ch\u1ea5t c\u1ee7a vi\u1ec7c t\u0103ng t\u1ed1c do m\u1ea1ng ph\u00e2n ph\u1ed1i n\u1ed9i dung (CDN) c\u0169ng c\u00f3 m\u1ed1i li\u00ean h\u1ec7 m\u1eadt thi\u1ebft v\u1edbi DNS. Khi b\u1ea1n s\u1eed d\u1ee5ng d\u1ecbch v\u1ee5 CDN, b\u1ea1n c\u1ea7n ch\u1ec9 \u0111\u1ecbnh t\u00ean mi\u1ec1n c\u1ee7a m\u00ecnh th\u00f4ng qua b\u1ea3n ghi CNAME \u0111\u1ebfn t\u00ean mi\u1ec1n do nh\u00e0 cung c\u1ea5p CDN cung c\u1ea5p. Sau \u0111\u00f3, c\u00e1c y\u00eau c\u1ea7u t\u1eeb ng\u01b0\u1eddi d\u00f9ng \u0111\u1ed1i v\u1edbi t\u00ean mi\u1ec1n c\u1ee7a b\u1ea1n s\u1ebd \u0111\u01b0\u1ee3c t\u1ef1 \u0111\u1ed9ng chuy\u1ec3n h\u01b0\u1edbng \u0111\u1ebfn node l\u01b0u tr\u1eef cache c\u1ee7a CDN n\u1eb1m g\u1ea7n nh\u1ea5t v\u1edbi v\u1ecb tr\u00ed \u0111\u1ecba l\u00fd c\u1ee7a h\u1ecd v\u00e0 c\u00f3 t\u1ed1c \u0111\u1ed9 truy c\u1eadp nhanh nh\u1ea5t, t\u1eeb \u0111\u00f3 c\u1ea3i thi\u1ec7n \u0111\u00e1ng k\u1ec3 tr\u1ea3i nghi\u1ec7m truy c\u1eadp cho ng\u01b0\u1eddi d\u00f9ng tr\u00ean to\u00e0n th\u1ebf gi\u1edbi.<\/p>\n\n\n

\n\n
\n \u0110\u0103ng k\u00fd t\u00ean mi\u1ec1n UltaHost<\/strong>\n
H\u01a1n 300 \u0111u\u00f4i t\u00ean mi\u1ec1n, ch\u1ecdn g\u00f3i l\u01b0u tr\u1eef h\u00e0ng n\u0103m, t\u1eadn h\u01b0\u1edfng t\u00ean mi\u1ec1n mi\u1ec5n ph\u00ed! Chuy\u1ec3n t\u00ean mi\u1ec1n sang Ultahost \u0111\u1ec3 \u0111\u01b0\u1ee3c gia h\u1ea1n mi\u1ec5n ph\u00ed m\u1ed9t n\u0103m, .com $9.49 n\u0103m \u0111\u1ea7u ti\u00ean<\/div>\n <\/div>\n\n
\n \n \n \"\u0110\u0103ng\n \n \n <\/a>\n \n \n Truy c\u1eadp UltaHost <\/a>\n <\/div>\n <\/div>\n\n \n\n\n\n\n\n\n

K\u00edch ho\u1ea1t DNS Security Extensions (DNSSEC)<\/h3>\n\n\n\n

DNSSEC (Domain Name System Security Extensions) l\u00e0 m\u1ed9t c\u00f4ng ngh\u1ec7 nh\u1eb1m b\u1ea3o v\u1ec7 an ninh cho d\u1eef li\u1ec7u DNS b\u1eb1ng c\u00e1ch k\u00fd s\u1ed1 h\u00f3a ch\u00fang. C\u00f4ng ngh\u1ec7 n\u00e0y gi\u00fap ng\u0103n ch\u1eb7n c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng nh\u01b0 l\u00e0m \u00f4 nhi\u1ec5m b\u1ed9 \u0111\u1ec7m DNS (DNS cache) ho\u1eb7c chi\u1ebfm \u0111o\u1ea1t t\u00ean mi\u1ec1n (domain name hijacking), \u0111\u1ea3m b\u1ea3o r\u1eb1ng k\u1ebft qu\u1ea3 gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n m\u00e0 ng\u01b0\u1eddi d\u00f9ng nh\u1eadn \u0111\u01b0\u1ee3c kh\u00f4ng b\u1ecb s\u1eeda \u0111\u1ed5i. \u0110\u1ec3 b\u1eadt DNSSEC, b\u1ea1n c\u1ea7n th\u1ef1c hi\u1ec7n c\u00e1c thi\u1ebft l\u1eadp tr\u00ean m\u00e1y ch\u1ee7 t\u00ean mi\u1ec1n ch\u00ednh th\u1ee9c c\u1ee7a m\u00ecnh v\u00e0 c\u00f3 th\u1ec3 c\u1ea7n ph\u1ea3i t\u1ea3i c\u00e1c b\u1ea3n ghi DS (Domain System Security Records) l\u00ean nh\u00e0 cung c\u1ea5p d\u1ecbch v\u1ee5 \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n. Ng\u00e0y c\u00e0ng nhi\u1ec1u t\u00ean mi\u1ec1n c\u1ea5p cao (top-level domains) v\u00e0 b\u1ed9 gi\u1ea3i quy\u1ebft DNS c\u00f4ng c\u1ed9ng h\u1ed7 tr\u1ee3 DNSSEC, mang l\u1ea1i m\u1ed9t l\u1edbp b\u1ea3o m\u1eadt quan tr\u1ecdng cho qu\u00e1 tr\u00ecnh gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n.<\/p>\n\n\n\n

Ch\u1ea9n \u0111o\u00e1n s\u1ef1 c\u1ed1 v\u00e0 c\u00f4ng c\u1ee5 th\u01b0\u1eddng d\u00f9ng<\/h2>\n\n\n\n

C\u00e1c v\u1ea5n \u0111\u1ec1 v\u1ec1 gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n (domain name resolution) c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn t\u00ecnh tr\u1ea1ng trang web kh\u00f4ng th\u1ec3 truy c\u1eadp \u0111\u01b0\u1ee3c, ho\u1eb7c vi\u1ec7c g\u1eedi\/nh\u1eadn email th\u1ea5t b\u1ea1i. Vi\u1ec7c n\u1eafm v\u1eefng c\u00e1c c\u00f4ng c\u1ee5 v\u00e0 ph\u01b0\u01a1ng ph\u00e1p ch\u1ea9n \u0111o\u00e1n c\u01a1 b\u1ea3n l\u00e0 v\u00f4 c\u00f9ng quan tr\u1ecdng.<\/p>\n\n\n\n

S\u1eed d\u1ee5ng c\u00e1c c\u00f4ng c\u1ee5 nslookup v\u00e0 dig \u0111\u1ec3 th\u1ef1c hi\u1ec7n c\u00e1c truy v\u1ea5n.<\/h3>\n\n\n\n

`nslookup` v\u00e0 `dig` l\u00e0 hai c\u00f4ng c\u1ee5 d\u00f9ng \u0111\u1ec3 truy v\u1ea5n DNS qua d\u00f2ng l\u1ec7nh ph\u1ed5 bi\u1ebfn nh\u1ea5t. `nslookup` c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng tr\u00ean c\u1ea3 Windows v\u00e0 c\u00e1c h\u1ec7 \u0111i\u1ec1u h\u00e0nh thu\u1ed9c nh\u00f3m Unix; c\u00e1ch s\u1eed d\u1ee5ng r\u1ea5t \u0111\u01a1n gi\u1ea3n \u2013 v\u00ed d\u1ee5: `nslookup example.com` s\u1ebd truy v\u1ea5n th\u00f4ng tin v\u1ec1 b\u1ea3n ghi A (A record) c\u1ee7a t\u00ean mi\u1ec1n \u0111\u00f3. C\u00f4ng c\u1ee5 `dig` m\u1ea1nh m\u1ebd h\u01a1n nhi\u1ec1u, cung c\u1ea5p th\u00f4ng tin chi ti\u1ebft h\u01a1n, v\u00e0 th\u01b0\u1eddng \u0111\u01b0\u1ee3c c\u00e1c chuy\u00ean gia \u01b0a chu\u1ed9ng. V\u00ed d\u1ee5: `dig example.com A` ho\u1eb7c `dig example.com MX` s\u1ebd truy v\u1ea5n c\u00e1c lo\u1ea1i b\u1ea3n ghi c\u1ee5 th\u1ec3 (nh\u01b0 b\u1ea3n ghi A ho\u1eb7c b\u1ea3n ghi MX). L\u1ec7nh `dig +trace example.com` c\u00f3 th\u1ec3 m\u00f4 ph\u1ecfng to\u00e0n b\u1ed9 qu\u00e1 tr\u00ecnh truy v\u1ea5n DNS theo c\u00e1ch tu\u1ea7n t\u1ef1 (recursive), gi\u00fap b\u1ea1n theo d\u00f5i \u0111\u01b0\u1eddng d\u1eabn gi\u1ea3i quy\u1ebft y\u00eau c\u1ea7u truy v\u1ea5n.<\/p>\n\n\n\n

Ki\u1ec3m tra tr\u1ea1ng th\u00e1i lan truy\u1ec1n c\u1ee7a DNS.<\/h3>\n\n\n\n

Khi b\u1ea1n thay \u0111\u1ed5i c\u00e1c b\u1ea3n ghi DNS (ch\u1eb3ng h\u1ea1n nh\u01b0 thay \u0111\u1ed5i m\u00e1y ch\u1ee7 t\u00ean mi\u1ec1n ho\u1eb7c \u0111\u1ecba ch\u1ec9 IP), c\u00e1c b\u1ed9 \u0111\u1ec7m DNS tr\u00ean to\u00e0n th\u1ebf gi\u1edbi c\u1ea7n th\u1eddi gian \u0111\u1ec3 c\u1eadp nh\u1eadt th\u00f4ng tin m\u1edbi. Qu\u00e1 tr\u00ecnh n\u00e0y \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u201cs\u1ef1 lan truy\u1ec1n c\u1ee7a DNS\u201d (DNS propagation). Do th\u1eddi gian l\u00e0m m\u1edbi b\u1ed9 \u0111\u1ec7m c\u1ee7a c\u00e1c nh\u00e0 cung c\u1ea5p d\u1ecbch v\u1ee5 Internet (ISP) tr\u00ean to\u00e0n th\u1ebf gi\u1edbi kh\u00e1c nhau (\u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1edfi gi\u00e1 tr\u1ecb TTL \u2013 Time To Live), vi\u1ec7c thay \u0111\u1ed5i c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng ho\u00e0n to\u00e0n trong kho\u1ea3ng th\u1eddi gian t\u1eeb v\u00e0i ph\u00fat \u0111\u1ebfn 48 gi\u1edd. B\u1ea1n c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng c\u00e1c c\u00f4ng c\u1ee5 ki\u1ec3m tra lan truy\u1ec1n DNS tr\u1ef1c tuy\u1ebfn (nh\u01b0 whatsmydns.net) \u0111\u1ec3 theo d\u00f5i ngay l\u1eadp t\u1ee9c xem k\u1ebft qu\u1ea3 gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n c\u1ee7a b\u1ea1n t\u1ea1i c\u00e1c \u0111\u1ecba \u0111i\u1ec3m kh\u00e1c nhau tr\u00ean th\u1ebf gi\u1edbi c\u00f3 \u0111\u00e3 \u0111\u01b0\u1ee3c c\u1eadp nh\u1eadt th\u00e0nh gi\u00e1 tr\u1ecb m\u1edbi hay ch\u01b0a.<\/p>\n\n\n\n

Gi\u1ea3i th\u00edch t\u1ea7m quan tr\u1ecdng c\u1ee7a gi\u00e1 tr\u1ecb TTL (Time To Live)<\/h3>\n\n\n\n

TTL (Time To Live) l\u00e0 m\u1ed9t tham s\u1ed1 c\u1ef1c k\u1ef3 quan tr\u1ecdng trong c\u00e1c b\u1ea3n ghi DNS, \u0111\u01b0\u1ee3c \u0111o b\u1eb1ng gi\u00e2y. N\u00f3 th\u00f4ng b\u00e1o cho c\u00e1c m\u00e1y ch\u1ee7 DNS \u0111\u1ec7 quy v\u00e0 b\u1ed9 nh\u1edb \u0111\u1ec7m c\u1ee5c b\u1ed9 r\u1eb1ng b\u1ea3n ghi \u0111\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c l\u01b0u tr\u1eef trong bao l\u00e2u. Vi\u1ec7c thi\u1ebft l\u1eadp gi\u00e1 tr\u1ecb TTL ng\u1eafn (v\u00ed d\u1ee5: 300 gi\u00e2y) gi\u00fap c\u00e1c thay \u0111\u1ed5i trong b\u1ea3n ghi \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng nhanh ch\u00f3ng tr\u00ean to\u00e0n c\u1ea7u, ph\u00f9 h\u1ee3p v\u1edbi nh\u1eefng d\u1ecbch v\u1ee5 th\u01b0\u1eddng xuy\u00ean thay \u0111\u1ed5i. Ng\u01b0\u1ee3c l\u1ea1i, vi\u1ec7c thi\u1ebft l\u1eadp gi\u00e1 tr\u1ecb TTL d\u00e0i (v\u00ed d\u1ee5: 86400 gi\u00e2y, t\u1ee9c l\u00e0 m\u1ed9t ng\u00e0y) gi\u00fap gi\u1ea3m b\u1edbt \u00e1p l\u1ef1c l\u00ean m\u00e1y ch\u1ee7 DNS ch\u00ednh th\u1ee9c c\u1ee7a b\u1ea1n v\u00e0 t\u0103ng t\u1ed1c \u0111\u1ed9 gi\u1ea3i quy\u1ebft y\u00eau c\u1ea7u t\u1eeb ng\u01b0\u1eddi d\u00f9ng, nh\u01b0ng c\u00e1c thay \u0111\u1ed5i s\u1ebd \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng ch\u1eadm h\u01a1n. Tr\u01b0\u1edbc khi th\u1ef1c hi\u1ec7n b\u1ea5t k\u1ef3 thay \u0111\u1ed5i DNS quan tr\u1ecdng n\u00e0o (ch\u1eb3ng h\u1ea1n nh\u01b0 di chuy\u1ec3n m\u00e1y ch\u1ee7), b\u1ea1n n\u00ean gi\u1ea3m gi\u00e1 tr\u1ecb TTL c\u1ee7a c\u00e1c b\u1ea3n ghi li\u00ean quan tr\u01b0\u1edbc; sau khi qu\u00e1 tr\u00ecnh di chuy\u1ec3n ho\u00e0n t\u1ea5t v\u00e0 \u1ed5n \u0111\u1ecbnh, h\u00e3y \u0111\u1eb7t l\u1ea1i gi\u00e1 tr\u1ecb TTL v\u1ec1 m\u1ee9c b\u00ecnh th\u01b0\u1eddng.<\/p>\n\n\n\n

T\u00f3m l\u1ea1i<\/h2>\n\n\n\n

Gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n (Domain Name Resolution \u2013 DNS) l\u00e0 m\u1ed9t kh\u00e2u c\u1ed1t l\u00f5i trong c\u01a1 s\u1edf h\u1ea1 t\u1ea7ng Internet; d\u00f9 \u00edt \u0111\u01b0\u1ee3c ch\u00fa \u00fd nh\u01b0ng l\u1ea1i v\u00f4 c\u00f9ng quan tr\u1ecdng. T\u1eeb vi\u1ec7c \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n, c\u1ea5u h\u00ecnh c\u00e1c m\u00e1y ch\u1ee7 DNS ch\u00ednh th\u1ee9c, thi\u1ebft l\u1eadp c\u00e1c lo\u1ea1i b\u1ea3n ghi t\u00e0i nguy\u00ean, \u0111\u1ebfn vi\u1ec7c s\u1eed d\u1ee5ng c\u00e1c c\u00f4ng ngh\u1ec7 nh\u01b0 ph\u00e2n b\u1ed5 t\u1ea3i (load balancing), t\u0103ng t\u1ed1c b\u1eb1ng CDN (Content Delivery Network) v\u00e0 t\u0103ng c\u01b0\u1eddng b\u1ea3o m\u1eadt b\u1eb1ng DNSSEC (Domain Name System Security Extensions), m\u1ed7i b\u01b0\u1edbc \u0111\u1ec1u \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn t\u00ednh kh\u1ea3 d\u1ee5ng, b\u1ea3o m\u1eadt v\u00e0 hi\u1ec7u su\u1ea5t ho\u1ea1t \u0111\u1ed9ng c\u1ee7a trang web. Vi\u1ec7c hi\u1ec3u r\u00f5 c\u00e1ch th\u1ee9c ho\u1ea1t \u0111\u1ed9ng c\u1ee7a DNS, s\u1eed d\u1ee5ng hi\u1ec7u qu\u1ea3 c\u00e1c c\u00f4ng c\u1ee5 ch\u1ea9n \u0111o\u00e1n nh\u01b0 `nslookup`, `dig`, v\u00e0 qu\u1ea3n l\u00fd c\u1ea9n th\u1eadn c\u00e1c gi\u00e1 tr\u1ecb TTL (Time To Live) s\u1ebd gi\u00fap b\u1ea1n nhanh ch\u00f3ng x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c nguy\u00ean nh\u00e2n khi g\u1eb7p s\u1ef1 c\u1ed1 v\u1ec1 gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n, t\u1eeb \u0111\u00f3 d\u1ec5 d\u00e0ng th\u1ef1c hi\u1ec7n c\u00f4ng t\u00e1c b\u1ea3o tr\u00ec v\u00e0 t\u1ed1i \u01b0u h\u00f3a c\u1ea5u tr\u00fac trang web. N\u1eafm v\u1eefng \u201cngh\u1ec7 thu\u1eadt\u201d n\u00e0y l\u00e0 y\u1ebfu t\u1ed1 then ch\u1ed1t \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 truy c\u1eadp d\u1ecbch v\u1ee5 c\u1ee7a b\u1ea1n m\u1ed9t c\u00e1ch nhanh ch\u00f3ng, \u1ed5n \u0111\u1ecbnh v\u00e0 an to\u00e0n.<\/p>\n\n

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\r\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\"\u0110\u0103ng\r\n\t\t\t\t\t\t\t\t\t\r\n\t\t\t<\/div>\r\n\t\t\t\r\n\t\t\t\r\n\t\t\t
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\r\n\t\t\t\t\t\u0110\u0103ng k\u00fd t\u00ean mi\u1ec1n Bluehost<\/strong>\r\n\t\t\t\t\t\t\t\t\t<\/div>\r\n\t\t\t<\/div>\r\n\t\t<\/div>\r\n\t\t\t\tH\u1ed7 tr\u1ee3 tr\u00ecnh t\u1ea1o t\u00ean mi\u1ec1n AI, d\u1ecbch v\u1ee5 h\u1ed7 tr\u1ee3 24\/7<\/span>\r\n\t\t\t\t
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T\u1ea1o t\u00ean mi\u1ec1n b\u1eb1ng AI<\/div>\r\n\t\t\t\t\t\t\t\t\t\t\t\tTruy c\u1eadp Bluehost \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n \u2192<\/a>\r\n\t\t\t\t\t\t\t<\/div> \r\n\t\t<\/div>\r\n\t<\/div>\r\n\t\t\r\n\t\r\n\t
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\r\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\"WordPress.com\r\n\t\t\t\t\t\t\t\t\t\r\n\t\t\t<\/div>\r\n\t\t\t\r\n\t\t\t\r\n\t\t\t
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\r\n\t\t\t\t\tWordPress.com \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n<\/strong>\r\n\t\t\t\t\t\t\t\t\t<\/div>\r\n\t\t\t<\/div>\r\n\t\t<\/div>\r\n\t\t\t\tCh\u1ecdn g\u00f3i cao c\u1ea5p nh\u1ea5t \u0111\u1ec3 \u0111\u01b0\u1ee3c gi\u1ea3m gi\u00e1 l\u00ean \u0111\u1ebfn 69% + mi\u1ec5n ph\u00ed chuy\u1ec3n t\u00ean mi\u1ec1n, b\u1ea1n c\u00f3 th\u1ec3 \u0111\u0103ng k\u00fd t\u1eeb .com, .blog v\u00e0 h\u01a1n 350 \u0111u\u00f4i t\u00ean mi\u1ec1n kh\u00e1c.<\/span>\r\n\t\t\t\t
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Mua g\u00f3i thanh to\u00e1n h\u00e0ng n\u0103m, t\u00ean mi\u1ec1n mi\u1ec5n ph\u00ed n\u0103m \u0111\u1ea7u ti\u00ean<\/div>\r\n\t\t\t\t\t\t\t\t\t\t\t\tTruy c\u1eadp \u0110\u0103ng k\u00fd t\u00ean mi\u1ec1n WordPress.com \u2192<\/a>\r\n\t\t\t\t\t\t\t<\/div> \r\n\t\t<\/div>\r\n\t<\/div>\r\n\t\t\r\n<\/div>\r\n\r\n\r\n\n\n\n\n\n\n\n

FAQ \u5e38\u89c1\u95ee\u9898<\/h2>\n\n\n\n

Sau khi thay \u0111\u1ed5i th\u00f4ng tin DNS, t\u1ea1i sao trang web v\u1eabn hi\u1ec3n th\u1ecb trang c\u0169 khi \u0111\u01b0\u1ee3c truy c\u1eadp?<\/h3>\n\n\n\n

\u0110i\u1ec1u n\u00e0y th\u01b0\u1eddng x\u1ea3y ra do s\u1ef1 can thi\u1ec7p c\u1ee7a hai lo\u1ea1i b\u1ed9 \u0111\u1ec7m (cache) kh\u00e1c nhau. \u0110\u1ea7u ti\u00ean l\u00e0 b\u1ed9 \u0111\u1ec7m DNS: B\u1ed9 ph\u1eadn gi\u1ea3i quy\u1ebft \u0111\u1ecba ch\u1ec9 IP (DNS resolver) tr\u00ean m\u00e1y t\u00ednh c\u00e1 nh\u00e2n ho\u1eb7c nh\u00e0 cung c\u1ea5p d\u1ecbch v\u1ee5 Internet (ISP) c\u1ee7a b\u1ea1n c\u00f3 th\u1ec3 v\u1eabn \u0111ang l\u01b0u tr\u1eef c\u00e1c \u0111\u1ecba ch\u1ec9 IP c\u0169. B\u1ea1n c\u00f3 th\u1ec3 th\u1eed l\u00e0m m\u1edbi b\u1ed9 \u0111\u1ec7m DNS b\u1eb1ng c\u00e1ch ch\u1ea1y l\u1ec7nh `ipconfig \/flushdns` tr\u00ean Windows Command Prompt, ho\u1eb7c `sudo dscacheutil -flushcache` ho\u1eb7c `sudo systemd-resolve --flush-caches` tr\u00ean macOS\/Linux (l\u1ec7nh c\u1ee5 th\u1ec3 c\u00f3 th\u1ec3 kh\u00e1c t\u00f9y h\u1ec7 \u0111i\u1ec1u h\u00e0nh).<\/p>\n\n\n\n

Ti\u1ebfp theo l\u00e0 v\u1ea5n \u0111\u1ec1 li\u00ean quan \u0111\u1ebfn b\u1ed9 nh\u1edb \u0111\u1ec7m c\u1ee7a tr\u00ecnh duy\u1ec7t v\u00e0 b\u1ed9 nh\u1edb \u0111\u1ec7m c\u1ee7a m\u00e1y ch\u1ee7 trang web\/c\u00e1c d\u1ecbch v\u1ee5 CDN (Content Delivery Network). Ngay c\u1ea3 khi qu\u00e1 tr\u00ecnh gi\u1ea3i m\u00e3 DNS \u0111\u00e3 \u0111\u1ecbnh tuy\u1ebfn \u0111\u00fang \u0111\u1ebfn \u0111\u1ecba ch\u1ec9 IP m\u1edbi, tr\u00ecnh duy\u1ec7t v\u1eabn c\u00f3 th\u1ec3 l\u01b0u tr\u1eef n\u1ed9i dung trang web c\u0169 trong b\u1ed9 nh\u1edb \u0111\u1ec7m; ho\u1eb7c c\u00e1c quy t\u1eafc l\u01b0u tr\u1eef tr\u00ean m\u00e1y ch\u1ee7 m\u1edbi c\u00f3 th\u1ec3 khi\u1ebfn n\u1ed9i dung c\u0169 v\u1eabn \u0111\u01b0\u1ee3c hi\u1ec3n th\u1ecb t\u1ea1m th\u1eddi. H\u00e3y th\u1eed l\u00e0m m\u1edbi trang web m\u1ed9t c\u00e1ch th\u1ee7 c\u00f4ng b\u1eb1ng ph\u00edm Ctrl+F5, ho\u1eb7c x\u00f3a b\u1ed9 nh\u1edb \u0111\u1ec7m c\u1ee7a tr\u00ecnh duy\u1ec7t.<\/p>\n\n\n\n

S\u1ef1 kh\u00e1c bi\u1ec7t ch\u00ednh gi\u1eefa b\u1ea3n ghi CNAME v\u00e0 b\u1ea3n ghi A l\u00e0 g\u00ec?<\/h3>\n\n\n\n

B\u1ea3n ghi A (A record) th\u1ef1c hi\u1ec7n vi\u1ec7c \u00e1nh x\u1ea1 tr\u1ef1c ti\u1ebfp t\u00ean mi\u1ec1n (domain name) \u0111\u1ebfn m\u1ed9t \u0111\u1ecba ch\u1ec9 IP (IP address); v\u00ed d\u1ee5, n\u00f3 c\u00f3 th\u1ec3 ch\u1ec9 \u0111\u1ecbnh r\u1eb1ng example.com ph\u1ea3i \u0111\u01b0\u1ee3c truy c\u1eadp t\u1eeb \u0111\u1ecba ch\u1ec9 IP 192.0.2.1. \u0110\u00e2y ch\u00ednh l\u00e0 n\u1ec1n t\u1ea3ng c\u01a1 b\u1ea3n cho qu\u00e1 tr\u00ecnh gi\u1ea3i m\u00e3 (resolution) t\u00ean mi\u1ec1n.<\/p>\n\n\n\n

CNAME (Canonical Name) l\u00e0 lo\u1ea1i b\u1ea3n ghi \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111\u1ecbnh ngh\u0129a m\u1ed9t t\u00ean mi\u1ec1n l\u00e0 t\u00ean mi\u1ec1n kh\u00e1c (v\u00ed d\u1ee5: \u0111\u1ecbnh tuy\u1ebfn www.example.com \u0111\u1ebfn example.com). Gi\u00e1 tr\u1ecb c\u1ee7a m\u1ed9t b\u1ea3n ghi CNAME l\u00e0 m\u1ed9t t\u00ean mi\u1ec1n, ch\u1ee9 kh\u00f4ng ph\u1ea3i \u0111\u1ecba ch\u1ec9 IP. M\u1ed9t h\u1ea1n ch\u1ebf quan tr\u1ecdng l\u00e0 m\u1ed9t b\u1ea3n ghi CNAME kh\u00f4ng th\u1ec3 t\u1ed3n t\u1ea1i c\u00f9ng l\u00fac v\u1edbi c\u00e1c lo\u1ea1i b\u1ea3n ghi c\u00f3 c\u00f9ng t\u00ean (nh\u01b0 MX, TXT). V\u00ed d\u1ee5, b\u1ea1n kh\u00f4ng th\u1ec3 \u0111\u1eb7t c\u00f9ng l\u00fac m\u1ed9t b\u1ea3n ghi CNAME v\u00e0 m\u1ed9t b\u1ea3n ghi MX cho t\u00ean mi\u1ec1n example.com.<\/p>\n\n\n\n

S\u1ef1 kh\u00e1c bi\u1ec7t ch\u00ednh gi\u1eefa vi\u1ec7c s\u1eed d\u1ee5ng d\u1ecbch v\u1ee5 DNS mi\u1ec5n ph\u00ed v\u00e0 d\u1ecbch v\u1ee5 DNS c\u00f3 ph\u00ed n\u1eb1m \u1edf nh\u1eefng \u0111i\u1ec3m sau:<\/h3>\n\n\n\n

D\u1ecbch v\u1ee5 DNS mi\u1ec5n ph\u00ed (ch\u1eb3ng h\u1ea1n nh\u01b0 d\u1ecbch v\u1ee5 \u0111i k\u00e8m v\u1edbi nh\u00e0 \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n ho\u1eb7c g\u00f3i d\u1ecbch v\u1ee5 mi\u1ec5n ph\u00ed c\u1ee7a Cloudflare) th\u01b0\u1eddng \u0111\u00e1p \u1ee9ng \u0111\u01b0\u1ee3c nh\u1eefng nhu c\u1ea7u c\u01a1 b\u1ea3n. C\u00e1c d\u1ecbch v\u1ee5 DNS tr\u1ea3 ph\u00ed (nh\u01b0 Cloudflare Pro, AWS Route 53, DNS Made Easy) cung c\u1ea5p nhi\u1ec1u t\u00ednh n\u0103ng n\u00e2ng cao h\u01a1n, bao g\u1ed3m: hi\u1ec7u su\u1ea5t truy v\u1ea5n v\u00e0 kh\u1ea3 n\u0103ng x\u1eed l\u00fd cao h\u01a1n (QPS), b\u00e1o c\u00e1o ph\u00e2n t\u00edch chi ti\u1ebft h\u01a1n, ch\u1ee9c n\u0103ng gi\u1ea3i quy\u1ebft \u0111\u1ecba l\u00fd th\u00f4ng minh (GeoDNS), h\u1ed7 tr\u1ee3 API m\u1ea1nh m\u1ebd h\u01a1n, d\u1ecbch v\u1ee5 kh\u00e1ch h\u00e0ng t\u1ed1t h\u01a1n, v\u00e0 c\u00e1c cam k\u1ebft v\u1ec1 ch\u1ea5t l\u01b0\u1ee3ng d\u1ecbch v\u1ee5 (SLA) v\u1edbi m\u1ee9c \u0111\u1ed9 s\u1eb5n s\u00e0ng cao (ch\u1eb3ng h\u1ea1n nh\u01b0 \u0111\u1ed9 s\u1eb5n s\u00e0ng 99,991%).<\/p>\n\n\n\n

DNS hijacking (Hijacking DNS) l\u00e0 g\u00ec? L\u00e0m th\u1ebf n\u00e0o \u0111\u1ec3 ph\u00e1t hi\u1ec7n v\u00e0 ph\u00f2ng ng\u1eeba?<\/h3>\n\n\n\n

DNS hijacking l\u00e0 m\u1ed9t lo\u1ea1i t\u1ea5n c\u00f4ng m\u1ea1ng, trong \u0111\u00f3 k\u1ebb t\u1ea5n c\u00f4ng s\u1eed d\u1ee5ng c\u00e1c th\u1ee7 \u0111o\u1ea1n nh\u1ea5t \u0111\u1ecbnh \u0111\u1ec3 thay \u0111\u1ed5i k\u1ebft qu\u1ea3 truy v\u1ea5n DNS, khi\u1ebfn \u0111\u1ecba ch\u1ec9 web m\u00e0 b\u1ea1n mu\u1ed1n truy c\u1eadp b\u1ecb gi\u1ea3i m\u00e3 th\u00e0nh m\u1ed9t \u0111\u1ecba ch\u1ec9 IP sai l\u1ec7ch, th\u01b0\u1eddng l\u00e0 \u0111\u1ecba ch\u1ec9 IP c\u00f3 ch\u1ee9a m\u00e3 \u0111\u1ed9c h\u1ea1i.<\/p>\n\n\n\n

C\u00e1c ph\u01b0\u01a1ng ph\u00e1p \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh v\u1ea5n \u0111\u1ec1 bao g\u1ed3m: \n\u2013 Khi truy c\u1eadp v\u00e0o nhi\u1ec1u trang web n\u1ed5i ti\u1ebfng, b\u1ea1n b\u1ecb chuy\u1ec3n h\u01b0\u1edbng \u0111\u1ebfn c\u00f9ng m\u1ed9t trang web l\u1ea1; \n\u2013 K\u1ebft qu\u1ea3 truy c\u1eadp v\u00e0o c\u00f9ng m\u1ed9t trang web kh\u00e1c nhau khi s\u1eed d\u1ee5ng c\u00e1c m\u1ea1ng kh\u00e1c nhau (v\u00ed d\u1ee5: chuy\u1ec3n t\u1eeb 4G sang 5G tr\u00ean \u0111i\u1ec7n tho\u1ea1i); \n\u2013 Khi s\u1eed d\u1ee5ng c\u00e1c l\u1ec7nh `dig` ho\u1eb7c `nslookup` \u0111\u1ec3 tra c\u1ee9u th\u00f4ng tin, \u0111\u1ecba ch\u1ec9 IP tr\u1ea3 v\u1ec1 kh\u00f4ng tr\u00f9ng kh\u1edbp v\u1edbi nh\u1eefng g\u00ec b\u1ea1n bi\u1ebft ho\u1eb7c v\u1edbi k\u1ebft qu\u1ea3 t\u1eeb c\u00e1c ngu\u1ed3n \u0111\u00e1ng tin c\u1eady (nh\u01b0 DNS c\u00f4ng c\u1ed9ng).<\/p>\n\n\n\n

C\u00e1c bi\u1ec7n ph\u00e1p ph\u00f2ng ng\u1eeba bao g\u1ed3m: S\u1eed d\u1ee5ng nh\u00e0 \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n v\u00e0 d\u1ecbch v\u1ee5 gi\u1ea3i quy\u1ebft DNS h\u1ed7 tr\u1ee3 DNSSEC; \u0110\u1eb7t m\u1eadt kh\u1ea9u m\u1ea1nh cho b\u1ed9 \u0111\u1ecbnh tuy\u1ebfn c\u1ee7a b\u1ea1n v\u00e0 thay \u0111\u1ed5i \u0111\u1ecba ch\u1ec9 qu\u1ea3n tr\u1ecb m\u1eb7c \u0111\u1ecbnh; S\u1eed d\u1ee5ng c\u00e1c m\u00e1y ch\u1ee7 DNS c\u00f4ng c\u1ed9ng \u0111\u00e1ng tin c\u1eady tr\u00ean thi\u1ebft b\u1ecb c\u00e1 nh\u00e2n (ch\u1eb3ng h\u1ea1n nh\u01b0 8.8.8.8, 1.1.1.1); Ki\u1ec3m tra v\u00e0 \u0111\u1ea3m b\u1ea3o r\u1eb1ng c\u00e0i \u0111\u1eb7t DNS c\u1ee7a c\u00e1c thi\u1ebft b\u1ecb m\u1ea1ng (nh\u01b0 b\u1ed9 \u0111\u1ecbnh tuy\u1ebfn) kh\u00f4ng b\u1ecb s\u1eeda \u0111\u1ed5i.<\/p>","protected":false},"excerpt":{"rendered":"

B\u00e0i vi\u1ebft n\u00e0y tr\u00ecnh b\u00e0y m\u1ed9t c\u00e1ch h\u1ec7 th\u1ed1ng c\u00e1c kh\u00e1i ni\u1ec7m c\u1ed1t l\u00f5i v\u00e0 quy tr\u00ecnh ho\u1ea1t \u0111\u1ed9ng c\u1ee7a d\u1ecbch v\u1ee5 gi\u1ea3i quy\u1ebft t\u00ean mi\u1ec1n (Domain Name System \u2013 DNS). N\u1ed9i dung bao g\u1ed3m t\u1eeb vi\u1ec7c l\u1ef1a ch\u1ecdn v\u00e0 \u0111\u0103ng k\u00fd t\u00ean mi\u1ec1n, c\u1ea5u h\u00ecnh c\u00e1c m\u00e1y ch\u1ee7 ch\u00ednh th\u1ee9c (authoritative servers) c\u00f9ng c\u00e1c b\u1ea3n ghi DNS quan tr\u1ecdng, cho \u0111\u1ebfn vi\u1ec7c s\u1eed d\u1ee5ng c\u00e1c chi\u1ebfn l\u01b0\u1ee3c n\u00e2ng cao nh\u01b0 ph\u00e2n b\u1ed5 t\u1ea3i (load balancing), chuy\u1ec3n ti\u1ebfp s\u1ef1 c\u1ed1 (fault transfer) v\u00e0 CDN (Content Delivery Network) \u0111\u1ec3 t\u1ed1i \u01b0u h\u00f3a hi\u1ec7u su\u1ea5t v\u00e0 b\u1ea3o m\u1eadt h\u1ec7 th\u1ed1ng. \u0110\u00e2y l\u00e0 m\u1ed9t h\u01b0\u1edbng d\u1eabn th\u1ef1c h\u00e0nh \u0111\u1ea7y \u0111\u1ee7 v\u1ec1 quy tr\u00ecnh gi\u1ea3i<\/p>","protected":false},"author":7,"featured_media":0,"template":"","meta":{"_acf_changed":false,"footnotes":""},"tags":[],"knowledge_category":[279],"class_list":["post-12356538","knowledge_post","type-knowledge_post","status-publish","hentry","knowledge_category-domain"],"acf":{"site_seo_keywords":"\u57df\u540d\u89e3\u6790\uff0cDNS\uff0c\u57df\u540d\u8d2d\u4e70\uff0cDNS\u8bb0\u5f55\uff0c\u6743\u5a01\u57df\u540d\u670d\u52a1\u5668\uff0cDNS\u8d1f\u8f7d\u5747\u8861\uff0cCDN\u52a0\u901f\uff0cDNS\u6545\u969c\u8f6c\u79fb"},"_links":{"self":[{"href":"https:\/\/www.likacloud.com\/vi\/wp-json\/wp\/v2\/knowledge_posts\/12356538","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.likacloud.com\/vi\/wp-json\/wp\/v2\/knowledge_posts"}],"about":[{"href":"https:\/\/www.likacloud.com\/vi\/wp-json\/wp\/v2\/types\/knowledge_post"}],"author":[{"embeddable":true,"href":"https:\/\/www.likacloud.com\/vi\/wp-json\/wp\/v2\/users\/7"}],"version-history":[{"count":0,"href":"https:\/\/www.likacloud.com\/vi\/wp-json\/wp\/v2\/knowledge_posts\/12356538\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.likacloud.com\/vi\/wp-json\/wp\/v2\/media?parent=12356538"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.likacloud.com\/vi\/wp-json\/wp\/v2\/tags?post=12356538"},{"taxonomy":"knowledge_category","embeddable":true,"href":"https:\/\/www.likacloud.com\/vi\/wp-json\/wp\/v2\/knowledge_category?post=12356538"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}