Ukwehluleka kwe-DNS noma inkinga ye-MTU? Lapho isicelo sima khona ngempela

Ukwehluleka okubili kunikeza umsebenzisi umusho ofanayo: isiza asisebenzi. Kwenzeka ezingqimbeni ezihlukene, futhi umehluko yiwona onquma ukuthi uzoshintsha ini. Ukwehluleka kokuxazulula igama kuma ngaphambi kokuba noma yikuphi ukuxhumana kube khona. Ukwehluleka kosayizi wephakethe kwenzeka ngemva kokuba igama selixazululiwe nangemva kokuba ukuxhawana ngesandla kuqediwe, yingakho ikhasi liqala ukulayisha bese liyama. Thola isigaba ngaphambi kokuthola isethingi.

Ukwehluleka okubili ezingqimbeni ezihlukene

Ukuxazulula kuguqula igama libe ikheli, futhi akukho okunye ekuxhumaneni okungaqala kuze kube yilokho kuphumelela. Izinkinga ze-MTU zendlela zenzeka kamuva, lapho iphakethe elikhulu kunomkhawulo wokuxhumana kuthile likhishwa futhi umthumeli engalokothi aziswe. Okunye ukusesha; okunye ukwehluleka kokulethwa okubonakala kuphela ngaphezu kosayizi othile.

Izimpawu ziyehluka ngendlela ongayibona ngaphandle kwethuluzi. Ukwehluleka kwe-DNS kuyashesha futhi kuyagxeka: isiphequluli sithi iseva ayitholakali. Ukwehluleka kwe-MTU kuyingxenye: ikhasi liqala, ezinye izinsiza ziyafika, futhi impendulo enkulu noma ukulayisha kuyama.

Uma uphawu lwakho luyingxenye, yeka ukubheka i-DNS.

Isigaba 1: ingabe igama lixazululwa nhlobo

Sebenzisa amathuluzi okusesha weplathifomu ngegama lomsingathi eliqondile elisetshenziswa uhlelo. Igama eliyimfihlo ehhovisi lingadinga isixazululi sangaphakathi, futhi i-DNS evikelekile yesiphequluli ngokwayo ingasebenza ngendlela ehlukile kunesixazululi sesistimu yokusebenza, ngakho zombili zingavumelani ngegama elifanayo.

Buza isixazululi esizosetshenziswa yisistimu yokusebenza, bese uqhathanisa:

dig +short vpn.example.com
dig +short vpn.example.com @10.0.0.53

Uma ukuxazulula kuhluleka, inkinga isekuleyo nqubomgomo nasekufinyelelekeni kwayo. Ungathumeli amagama ayimfihlo kuma-sixazululi omphakathi ngokungahleliwe ukuze nje uthole ukuqhathanisa, ngoba ukuqhathanisa ngokwako kwembula amagama obufuna ukuwagcina engaphakathi.

Isigaba 2: ukudluliswa kuma kuphi

Uma igama lixazululwa nokuxhumana kuqala, bhala lapho umsebenzi uma khona. Ikhasi eliboniswayo bese liyama kwinsiza eyodwa, ukulayisha okufa endaweni engaguquki, noma ukulanda okukhulu okungapheli ngenkathi izicelo ezincane zisebenza — konke kuyizimpawu ezisesimweni sosayizi. Impendulo engaqali nakanye inesimo esihlukile.

Gcina iphoyinti lokugcina nendawo oya kuyo yohlelo kugxilile ngenkathi uqhathanisa, ngaphandle kwalokho ulinganisa izinguquko ezimbili ngesikhathi esisodwa. Ezinye izimbangela zingenzeka kulesi sigaba: amaphutha ensizakalo, ukulahleka, indlela yokuziphatha kwesihlungi nokuxhumana kabusha kwethaneli — konke kudala ukubambezeleka.

Ukubambezeleka okukodwa okuphindwayo kubaluleke ngaphezu kweziyishumi zezindaba.

Kungani i-MTU ilimaza kuphela ngemva kokuxhawana ngesandla

Ukuxhawana ngesandla kwe-TCP kusebenzisa amaphakethe amancane, ngakho kuyaphumelela endleleni engenakuthwala ingxenye yosayizi ogcwele. Ukwehluleka kubonakala lapho umthumeli ekhipha iphakethe elikhulu elinebhithi yokuvimbela ukuhlukaniswa, ukuxhumana kukulahla, futhi umyalezo we-ICMP obuzobika umkhawulo ungezi nakanye ngoba isihlungi usudle wona. Bese umthumeli uzama futhi usayizi ofanayo futhi ukudluliswa kuyama.

Yingakho uphawu luxhomeke kosayizi futhi luphindwa esikhundleni sokuba kungahleliwe. Lokhu futhi kuchaza ukuthi kungani i-ping kumsingathi ingafakazi lutho, ngoba umsindo we-ICMP omncane ungadlula indlela engayothwali umthwalo wosayizi ogcwele. Linganisa usayizi kusuka kuzo zombili izingxenye zendlela uma unakho. Umkhawulo obonakala ohlangothini olulodwa kuphela akusona i-MTU yethaneli, ukungalingani kokuhlela.

Linganisa usayizi ngokucacile esikhundleni sokuqagela:

ping -M do -s 1472 203.0.113.20
tracepath 203.0.113.20

Shintsha ingqimba eyodwa, bese ufakazela

Emagameni, shintsha inqubomgomo yesixazululi bese ugijima futhi ukusesha okufanayo. Kusayizi, sebenzisa inqubo ye-MTU nemithelela yokuqala ebhaliwe kanye nokulungela ukubuyela emuva, ngoba ukukhawulela i-MSS ungayazi i-MTU yangempela yethaneli kushintsha ukubambezeleka okukodwa nokunye.

Ikhasi elilayisha kanye ngemva kokushintshwa kwezilungiselelo ezimbalwa alikhombisi ukuthi yikuphi ukulungiswa. Shintsha into eyodwa, gijima futhi uhlolo olufanayo, futhi gcina umphumela eduze kwesigaba sokuqala sokwehluleka osibhalile.

Yilowo mbhalo ovimbela i-DNS, usayizi wephakethe nokuqinisekisa ukuthi kungaphenduki inqwaba yezindlela zokuzungeza ezihlala njalo ezingachazwa muntu. Ukuhlola nge-IP eluhlaza yisibonelo esihle sendlela emfushane eshintsha ubunikazi be-TLS, futhi ukuvala ukuqinisekisa isitifiketi ukuze ukuqhathanisa kuphumelele akusona isiqondiso.