Hauv cov ntsiab lus yooj yim, Lub Npe Lub Npe System (DNS) yog ib qho kev sau ntawm cov ntaub ntawv uas txhais cov hostnames rau IP chaw nyob.
DNS feem ntau hu ua phau ntawv xov tooj hauv is taws nem vim nws hloov pauv yooj yim-rau-nco hostnames xws li www.google.com, rau IP chaw nyob xws li 216.58.217.46. Qhov no yuav tshwm sim tom qab lub scenes tom qab koj ntaus URL rau hauv lub web browser qhov chaw nyob bar.
Yog tsis muaj DNS (thiab tshwj xeeb tshaj yog kev tshawb fawb xyaw xws li Google), kev taug kev hauv is taws nem tsis yooj yim vim peb yuav tsum nkag mus rau IP chaw nyob ntawm txhua lub vev xaib uas peb xav mus xyuas.
DNS ua haujlwm li cas?
Yog tias nws tseem tsis tau meej meej, lub tswv yim tseem ceeb ntawm DNS ua nws txoj haujlwm yog qhov yooj yim: txhua lub vev xaib chaw nyob nkag mus rau hauv lub vev xaib (xws li Chrome, Safari, lossis Firefox) raug xa mus rau DNS server, uas nkag siab yuav ua li cas qhia lub npe rau nws qhov chaw nyob IP.
Nws yog tus IP chaw uas cov cuab yeej siv sib txuas lus nrog ib leeg vim lawv tsis tuaj yeem thiab tsis xa cov ntaub ntawv siv lub npe xws li www.google.com, www.youtube.com, thiab lwm yam. nkag mus rau lub npe yooj yim rau cov vev xaib no thaum DNS ua txhua qhov kev tshawb nrhiav rau peb, muab rau peb nyob ze-tsim nkag mus rau qhov chaw nyob IP uas xav tau los qhib nplooj ntawv peb xav tau.
Dua, www.microsoft.com, www.lifewire.com, www.amazon.com, thiab txhua lwm lub npe lub vev xaib tsuas yog siv rau peb txoj kev yooj yim vim nws yooj yim dua rau nco cov npe dua li nco ntsoov lawv qhov chaw nyob IP.
Khoos phis tawj hu ua cov hauv paus servers yog lub luag haujlwm khaws cia IP chaw nyob rau txhua tus sau npe saum toj kawg nkaus. Thaum lub vev xaib raug thov, nws yog lub hauv paus server uas ua cov ntaub ntawv ua ntej txhawm rau txheeb xyuas cov kauj ruam tom ntej hauv cov txheej txheem nrhiav. Tom qab ntawd, lub npe sau npe raug xa mus rau Domain Name Resolver (DNR), uas nyob hauv ISP, txhawm rau txiav txim siab qhov chaw nyob IP. Thaum kawg, cov ntaub ntawv no raug xa rov qab mus rau lub cuab yeej koj thov los ntawm.
Yuav ua li cas ntxuav DNS
Kev khiav haujlwm xws li Windows thiab lwm tus yuav khaws IP chaw nyob thiab lwm yam ntaub ntawv hais txog lub npe hostnames hauv zos kom lawv tuaj yeem nkag tau sai dua li yuav tsum tau mus cuag DNS server ib txwm. Thaum lub khoos phis tawj nkag siab tias qee lub npe hostname yog sib txuas nrog qee qhov chaw nyob IP, cov ntaub ntawv ntawd raug tso cai khaws cia, lossis cached ntawm lub cuab yeej.
Thaum nco ntsoov cov ntaub ntawv DNS muaj txiaj ntsig, qee zaum nws tuaj yeem ua tsis zoo lossis tsis tu ncua. Feem ntau lub operating system tshem tawm cov ntaub ntawv no tom qab qee lub sijhawm, tab sis yog tias koj muaj teeb meem nkag mus rau lub vev xaib thiab koj xav tias nws yog vim qhov teeb meem DNS, thawj kauj ruam yog yuam-rho tawm cov ntaub ntawv no los ua chaw tshiab, hloov kho DNS cov ntaub ntawv.
Koj yuav tsum tuaj yeem rov pib dua koj lub computer yog tias koj muaj teeb meem nrog DNS vim tias DNS cache tsis khaws cia los ntawm kev rov pib dua. Txawm li cas los xij, tshem tawm cov cache manually nyob rau hauv qhov chaw ntawm reboot yog sai dua.
Koj tuaj yeem yaug DNS hauv Windows los ntawm Command Prompt nrog ipconfig / flushdns hais kom ua. Lub vev xaib Kuv DNS yog dab tsi? muaj cov lus qhia ua qhov no ntawm macOS thiab Linux.
Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias, nyob ntawm seb koj lub router tshwj xeeb raug teeb tsa li cas, cov ntaub ntawv DNS yuav raug muab khaws cia rau ntawd thiab. Yog hais tias ntxuav lub DNS cache ntawm koj lub computer tsis kho koj qhov teeb meem DNS, koj yuav tsum sim rov pib dua koj lub router kom yaug qhov DNS cache.
Nkag mus rau hauv cov ntaub ntawv hosts tsis raug tshem tawm thaum DNS cache raug ntxuav kom huv. Koj yuav tsum kho cov ntaub ntawv hosts kom tshem tawm hostnames thiab IP chaw nyob uas khaws cia rau ntawd.
Malware tuaj yeem cuam tshuam rau DNS nkag
Vim tias DNS yog lub luag haujlwm rau coj cov npe hostnames rau qee qhov chaw nyob IP, nws yuav tsum pom tseeb tias nws yog lub hom phiaj tseem ceeb rau kev ua phem. Hackers tuaj yeem hloov koj qhov kev thov rau cov peev txheej ua haujlwm ib txwm ua rau ib qho cuab yeej rau sau cov passwords lossis ua haujlwm rau malware.
DNS lom thiab DNS spoofing yog cov ntsiab lus siv los piav qhia txog kev tawm tsam ntawm DNS tus neeg daws teeb meem cache rau lub hom phiaj ntawm kev hloov pauv lub npe hostname mus rau qhov chaw IP sib txawv dua li qhov tseeb tau muab rau lub npe hostname, zoo redirecting qhov chaw koj xav mus.. Qhov no yog ib txwm ua hauv kev rau siab coj koj mus rau lub vev xaib uas muaj cov ntaub ntawv tsis zoo lossis ua rau phishing tawm tsam kom ntxias koj nkag mus rau lub vev xaib zoo sib xws txhawm rau txhawm rau nyiag koj cov ntawv pov thawj nkag.
Feem ntau cov kev pabcuam DNS muab kev tiv thaiv cov hom kev tawm tsam no.
Lwm txoj hauv kev rau cov neeg tawm tsam cuam tshuam rau DNS nkag yog siv cov ntaub ntawv hosts. Cov ntaub ntawv hosts yog cov ntaub ntawv khaws cia hauv zos uas tau siv los ntawm DNS ua ntej DNS tau dhau los ua cov cuab yeej siv dav rau kev daws cov npe hostnames, tab sis cov ntaub ntawv tseem muaj nyob hauv cov haujlwm nrov. Cov ntaub ntawv khaws cia hauv cov ntaub ntawv ntawd override DNS server chaw, yog li nws yog lub hom phiaj rau malware.
Ib txoj hauv kev yooj yim los tiv thaiv cov ntaub ntawv hosts los ntawm kev kho yog kos nws ua cov ntawv nyeem nkaus xwb. Hauv Windows, tsuas yog mus rau lub nplaub tshev uas muaj cov ntaub ntawv hosts:
%Systemdrive%\Windows\System32\drivers\etc\
Right-click it or kais-and-thold, xaiv Properties, thiab mam li tso ib daim tshev rau hauv lub thawv ib sab ntawm Read-onlytus yam ntxwv.
Xav paub ntxiv ntawm DNS
ISP uas tab tom ua haujlwm rau koj hauv internet tau muab DNS servers rau koj cov khoom siv siv (yog tias koj txuas nrog DHCP), tab sis koj tsis raug yuam kom lo nrog cov DNS servers. Lwm cov servers tuaj yeem muab cov ntawv sau npe los taug qab cov vev xaib uas tau mus xyuas, kev tshaj tawm blockers, cov neeg laus lub vev xaib lim dej, thiab lwm yam nta. Saib daim ntawv teev npe dawb thiab pej xeem DNS servers rau qee qhov piv txwv ntawm lwm DNS servers.
Txawm hais tias lub khoos phis tawj siv DHCP kom tau txais IP chaw nyob lossis yog tias nws siv qhov chaw nyob IP zoo li qub, koj tseem tuaj yeem txhais cov kev cai DNS servers. Txawm li cas los xij, yog tias nws tsis tau teeb tsa nrog DHCP, koj yuav tsum qhia cov DNS servers nws yuav tsum siv.
Ntseeg DNS neeg rau zaub mov teeb tsa ua qhov tseem ceeb tshaj qhov tsis raug, teeb tsa saum toj saud. Hauv lwm lo lus, nws yog qhov chaw DNS ze tshaj plaws rau lub cuab yeej uas lub cuab yeej siv. Piv txwv li, yog tias koj hloov DNS server teeb tsa ntawm koj lub router rau qee yam tshwj xeeb, ces txhua yam khoom siv txuas nrog routers yuav kuj siv cov DNS servers. Txawm li cas los xij, yog tias koj mam li hloov DNS server nqis ntawm lub PC rau qee yam sib txawv, lub khoos phis tawj ntawd yuav siv cov DNS servers sib txawv dua li txhua lwm yam khoom siv txuas nrog tib lub router.
Qhov no yog qhov laj thawj uas cuam tshuam DNS cache ntawm koj lub khoos phis tawj tuaj yeem tiv thaiv cov vev xaib los ntawm kev thauj khoom txawm tias tib lub qhib ib txwm qhib ntawm lub khoos phis tawj sib txawv ntawm tib lub network.
Txawm hais tias cov URLs peb ib txwm nkag mus rau hauv peb lub vev xaib browser yog cov npe yooj yim-rau-nco zoo li www.lifewire.com, koj tuaj yeem siv tus IP chaw nyob uas tus tswv lub npe taw qhia rau, xws li https://151.101. 1.121) nkag mus rau tib lub vev xaib. Qhov no yog vim tias koj tseem nkag mus rau tib lub server los ntawm txoj kev-ib txoj hauv kev (siv lub npe) tsuas yog yooj yim rau kev nco.
Ntawm daim ntawv ntawd, yog tias muaj qee qhov teeb meem nrog koj lub cuab yeej hu rau DNS server, koj tuaj yeem hla dhau los ntawm kev nkag mus rau IP chaw nyob rau hauv qhov chaw nyob bar es tsis txhob siv lub npe host. Cov neeg feem coob tsis khaws cov npe hauv zos ntawm IP chaw nyob uas sib haum rau hostnames, txawm li cas los xij, vim tias tom qab tag nrho, qhov ntawd yog tag nrho lub hom phiaj ntawm kev siv DNS server hauv thawj qhov chaw.
Qhov no tsis ua haujlwm nrog txhua lub vev xaib thiab IP chaw nyob vim qee lub vev xaib tau sib koom hosting teeb tsa, uas txhais tau hais tias nkag mus rau tus server tus IP chaw nyob los ntawm lub vev xaib browser tsis piav qhia txog nplooj ntawv twg, tshwj xeeb, yuav tsum qhib.
Qhov "phau xov tooj" saib uas txiav txim siab tus IP chaw nyob raws li lub npe host npe hu ua DNS ntsia rau pem hauv ntej. Qhov opposite, rov qab DNS lookup, yog lwm yam uas yuav ua tau nrog DNS servers. Qhov no yog thaum lub hostname raug txheeb xyuas los ntawm nws tus IP chaw nyob. Hom kev tshawb nrhiav no tso siab rau lub tswv yim tias tus IP chaw nyob cuam tshuam nrog lub npe tshwj xeeb yog qhov chaw nyob IP zoo li qub.
DNS databases khaws ntau yam ntxiv rau IP chaw nyob thiab hostnames. Yog tias koj tau teeb tsa email ntawm lub vev xaib lossis hloov lub npe sau npe, koj tuaj yeem khiav mus rau hauv cov ntsiab lus xws li domain name aliases (CNAME) thiab SMTP mail exchangers (MX).
FAQ
Koj hloov DNS servers li cas?
Txhawm rau hloov DNS servers hauv Windows, koj tuaj yeem siv Command Prompt lossis mus dhau qhov chaw Windows. Kev siv Windows nqis yog qhov zoo dua yog tias koj tsis xis nyob siv kab hais kom ua.
Koj pom DNS servers li cas?
Muaj ntau ntau DNS servers sib txawv nyob rau ntawd, yog li koj tuaj yeem saib los ntawm cov npe ntawm DNS servers txog thaum koj pom ib qho koj nyiam. Lifewire muaj cov npe nrog cov lus pom zoo rau qhov zoo tshaj plaws dawb DNS servers tawm muaj.
Dynamic DNS yog dab tsi?
Tsis zoo li DNS, uas tsuas yog ua haujlwm nrog IP chaw nyob zoo li qub, dynamic DNS (lossis DDNS) kuj txhawb nqa IP chaw nyob. Yog li ntawd, koj tuaj yeem siv DDNS kev pabcuam los tuav koj lub vev xaib los ntawm koj lub tsev lossis tswj hwm koj lub network hauv tsev.
