DNS yog tus txhais lus ntawm hostnames thiab IP chaw nyob
Hauv cov lus yooj yooj yim, Cov Thaj Tsam Lub Npe (DNS) yog ib phau ntawm databases uas txhais cov hostnames rau IP qhov chaw .
DNS feem ntau xa mus rau hauv internet phau ntawv xov tooj vim nws hloov siab tau yooj yim-rau-nco ntsoov hostnames li www.google.com , rau IP qhov chaw xws li 216.58.217.46 . Qhov no yuav siv qhov chaw tom qab lub scenes tom qab koj ntaus qhov URL rau hauv lub web browser qhov chaw nyob.
Tsis muaj DNS (thiab tshwj xeeb tshaj yog tshawb fawb xyaw xws li Google), navigating hauv internet yuav tsis yooj yim vim peb yuav tau nkag mus rau qhov chaw nyob ntawm IP ntawm txhua lub website uas peb xav tuaj xyuas.
DNS Ua Hauj Lwm Li Cas?
Yog hais tias nws tseem tsis meej, cov tswv yim yooj yim rau DNS ua nws txoj hauj lwm yooj yim theej: txhua lub website chaw nkag mus rau hauv lub web browser (xws li Chrome, Safari, lossis Firefox) xa mus rau DNS server , uas to taub li cas map lub npe ntawd rau nws qhov chaw nyob zoo IP.
Nws yog qhov chaw tus IP uas siv cov cuab yeej sib txuas lus nrog lwm tus vim lawv tsis muaj peev xwm thiab tsis tso lus qhia siv lub npe xws li www.google.com , www.youtube.com , thiab lwm yam. Peb tau nkag mus rau lub npe yooj yooj yim rau cov websites no thaum DNS tsis yog tag nrho cov lookups rau peb, muab rau peb nyob ze-instant nkag mus rau qhov chaw tus IP zoo xav tau los qhib cov nplooj ntawv peb xav tau.
Ntxiv dua thiab, www.microsoft.com, www. , www.amazon.com , thiab txhua lub npe ntawm lub website tsuas yog siv rau peb kev yooj yim vim nws yooj yim dua nco qab cov npe no kom nco qab lawv cov IP chaw.
Cov computers hu ua cov hauv paus servers yog lub luag haujlwm rau khaws cia cov chaw tus IP rau txhua tus neeg sau . Thaum twg lub website tau thov, nws yog lub hauv paus tus neeg ua haujlwm uas ua raws li cov ntaub ntawv ua ntej thiaj li paub cov kauj ruam tom ntej hauv kev saib xyuas. Tom qab ntawd, lub npe no raug xa mus rau Lub Tuam Thawj Lub Tuam Tsawg (DNR), uas nyob hauv ib qho ISP , los txiav txim qhov tseeb IP chaw nyob. Thaum kawg, cov ntaub ntawv no xa rov qab tuaj rau lub tshuab koj thov ntawm.
Yuav ua li cas yaug DNS
Operating systems zoo li lub qhov rais thiab lwm tus yuav khaws cov IP chaw nyob thiab lwm yam ntaub ntawv hais txog hostnames Senior kom lawv tuaj yeem tau sai dua li muaj ib txwm tuaj yeem mus cuag DNS server. Thaum lub computer nkag siab tias ib lub hostname qee lub npe nrog ib tus IP chaw nyob, cov ntaub ntawv raug tso cai muab khaws tseg, lossis cached ntawm tus ntaus ntawv.
Thaum uas nco ntsoov DNS cov ntaub ntawv yeej pab tau, nws qee zaum ua qoob loo los yog outdated. Feem ntau qhov kev khiav hauj lwm uas tshem tawm cov ntaub ntawv no tom qab lub sijhawm, tab sis yog tias koj muaj teeb meem nkag mus rau lub website thiab koj xav tias nws yog vim muaj qhov teeb meem ntawm DNS, thawj kauj ruam yog yuam kom-rho tawm cov ntaub ntawv no kom chaw tshiab, tshiab DNS cov ntaub ntawv.
Koj yuav tsum muaj peev xwm pib reboot koj lub computer yog tias koj muaj teeb meem nrog DNS vim hais tias cov DNS cache tsis khaws cia los ntawm kev rov qab. Txawm li cas los xij, khiav tawm lub cache ntawm qhov chaw ntawm qhov kev cuam tshuam kom sai dua.
Koj tuaj yeem yoov yau rau DNS hauv qhov rais los ntawm kev hais kom ua tiav nrog lub ipconfig / flushdns hais kom ua . Lub vev xaib Kuv lub npe yog dab tsi? muaj cov lus qhia ntawm kev ntaiv ntawm DNS rau txhua version ntawm qhov rais , ntxiv rau macOS thiab Linux.
Nws tseem ceeb heev uas yuav tsum nco ntsoov tias, nyob ntawm seb koj tus router muaj teeb tsa li cas, DNS cov ntaub ntawv khaws tseg yuav khaws cia ib yam nkaus thiab. Yog hais tias daus tus DNS cache rau hauv koj lub computer tsis kho koj cov teeb meem DNS, koj yuav tsum twv yuav tsum sim rov qab ua koj tus router los yaug tawm tias DNS cache.
Lus Cim: Nkag rau hauv cov ntaub ntawv hom tsis raug muab tshem tawm thaum lub DNS cache yog wiped huv si. Koj yuav tsum hloov cov ntaub ntawv kom tiav los tshem tawm cov hostnames thiab IP chaw nyob uas muab rau.
Malware Yuav cuam tshuam DNS Nkag
Muab hais tias DNS yog lub luag hauj lwm rau kev coj cov hostnames rau tej tus IP chaw nyob, nws yuav tsum pom tseeb tias nws yog ib qho hom phiaj rau kev siab phem. Hackers tuaj yeem hloov koj daim ntawv thov rau ib qho chaw ua hauj lwm rau ib qho uas yog qhov cuab yeej rau kev sau cov passwords los yog kev pab malware .
DNS lom thiab DNS spoofing yog cov ntsiab lus siv los piav qhia txog kev tua ntawm DNS resolver lub cache rau lub hom phiaj ntawm redirecting ib tug hostname rau ib tus IP ntau dua li qhov tseeb uas tau muab rau tus hostname, zoo qhov chaw koj npaj mus. Qhov no feem ntau yuav ua rau koj coj mus rau ib lub vas sab uas muaj cov ntaub ntawv siab phem los yog ua tus phom phom rau tricking koj mus nkag ib lub website zoo li qhov yuav kom nyiag koj cov ntawv tso npe nkag.
Feem ntau DNS cov kev pab tiv thaiv cov kev tawm tsam no.
Lwm txoj kev rau attackers los cuam tshuam rau DNS nkag yog siv cov hom ntaub ntawv. Cov ntaub ntawv hom yog ib phau ntawv khaws tseg hauv zos uas tau muab siv ua qhov ntawm DNS ua ntej DNS tiag los ua ib qho cuab tam ntau rau kev daws cov hostnames, tab sis cov ntaub ntawv tseem muaj nyob hauv cov haujlwm khiav lag luam. Nkag khaws cia rau hauv cov ntaub ntawv ntawd ua kom override DNS server settings, yog li nws yog ib qho hom phiaj rau malware.
Ib txoj kev yooj yim uas yuav tiv thaiv cov ntaub ntawv ntawm cov ntaub ntawv ntawm qhov ua yog kho tau nws yog ib qho chaw nyeem ntawv nkaus xwb . Nyob rau hauv Qhov rais, cia li rov qab mus rau lub nplaub tshev uas muaj cov hom ntaub ntawv tseem ceeb: % Systemdrive% \ Windows \ System32 \ drivers \ etc. Txoj cai-nias nws los yog kais-thiab-tuav, xaiv Properties , thiab mam li tso ib daim tshev rau hauv lub thawv ntawm tus cim nkaus xwb .
Xav paub ntxiv txog DNS
Qhov ISP uas tam sim no muab rau koj Internet nkag tau muab DNS servers rau koj li siv (yog tias koj nyob nraum nrog DHCP ), tab sis koj tsis yuam kom lo nrog cov DNS servers. Lwm cov servers yuav muab cov nta cov cuab yeej los nrhiav cov websites, cov kev tshaj tawm, cov neeg laus lub website, thiab lwm cov nta. Saib ntawm no daim ntawv dawb thiab pej xeem DNS Servers rau qee cov qauv ntawm lwm DNS servers.
Txawm tias lub computer siv DHCP kom tau txais qhov chaw tus IP lossis yog nws siv qhov chaw nyob hauv IP , koj tuaj yeem piav txog cov kev cai DNS servers. Txawm li cas los xij, yog tias nws tsis teeb nrog DHCP, koj yuav tsum qhia meej rau cov DNS servers nws yuav tsum siv.
Qhia tau meej DNS cov chaw rau zaub mov noj ua ntej lawm implicit, saum-down nqis. Hauv lwm lo lus, nws yog qhov DNS settings ze tshaj plaws rau ib tug ntaus ntawv tias tus ntaus ntawv siv. Piv txwv li, yog tias koj hloov DNS qhov chaw rau zaub mov hauv koj lub router rau ib yam dab tsi, ces tag nrho cov khoom siv txuas nrog hais tias router yuav tau siv cov DNS servers. Txawm li cas los xij, yog tias koj ho hloov DNS qhov chaw nyob hauv lub PC rau ib yam dab tsi sib txawv , tias lub computer yuav siv ntau DNS servers tshaj tag nrho lwm yam khoom txuas nrog tib lub router.
Qhov no yog vim li cas tias corrupted DNS cache ntawm koj lub computer tuaj yeem tiv thaiv cov websites ntawm kev thauj khoom txawm yog tib yam qhib txhua zaus ntawm lub computer txawv ntawm tib lub network.
Txawm hais tias cov URLs peb nquag nkag rau hauv peb qhov web browsers yog cov npe yooj yim-rau-nco ntsoov xws li www. , koj tuaj yeem siv qhov chaw tus IP uas lub hostname taw rau, zoo li https: //151.101.1.121) mus saib tib lub website. Qhov no yog vim hais tias koj tseem nyob nraum tib tus tib neeg siv tib txoj kev - ib txoj kev (siv lub npe) yog yooj yim dua nco qab.
Nyob rau ntawm daim ntawv ntawd, yog tias muaj qee qhov teeb meem nrog koj ntaus ntawv hu rau DNS server, koj yuav ib txwm bypass nws los ntawm nkag mus rau qhov chaw nyob tus IP rau hauv qhov chaw nyob ntawm chaw siv lub hostname. Neeg feem coob tsis khaws ib daim ntawv teev npe ntawm cov chaw nyob IP uas sib piv rau hostnames, tab sis, vim hais tias tom qab tag nrho, uas yog tag nrho lub hom phiaj ntawm kev siv ib tug DNS neeg rau zaub mov hauv thawj qhov chaw.
Lus cim: Qhov no tsis ua hauj lwm nrog txhua lub vas sab thiab IP chaw txij li qee qhov chaw qiv ntawv tau sib koom tes, uas txhais tau hais tias nkag mus rau tus neeg siv qhov IP qhov chaw nyob ntawm lub web browser tsis piav qhia cov nplooj ntawv, tshwj xeeb, yuav tsum qhib.
Tus "xov tooj hauv phau ntawv" uas tshawb pom qhov chaw tus IP raws li lub npe hu ua hu ua DNS saib ua ntej . Qhov ntxeev lus, rov qab DNS lookup , yog lwm yam uas yuav ua tau nrog DNS servers. Qhov no yog thaum lub hostname yog qhia los ntawm nws tus IP chaw nyob. Hom kev saib xyuas no cia siab rau ntawm lub tswv yim tias IP chaw nyob nrog cov npe ntawd yog tus IP chaw nyob zoo li qub.
DNS databases khw ntau ntau yam ntxiv rau IP chaw nyob thiab hostnames. Yog hais tias koj twb tau teem email rau hauv ib lub website lossis xa mus rau ib lub npe, koj tuaj yeem khiav mus rau hauv cov ntsiab lus xws li sau npe hu ua Aliases (CNAME) thiab SMTP mail exchangers (MX).