I-MTU yomzila ngamunye ku-Linux: izilawuli ezintathu zosayizi, umzila owodwa
I-MTU yesixhumi, i-MTU yomzila kanye nomkhawulo we-MSS kusebenza ezingqimbeni ezihlukene. Xhuma isabelomali emzileni owinayo ekusesheni, futhi gcina ushintsho lubuyiseka.
Izilungiselelo ezintathu kuklayenti le-Linux zizwakala zithi «yenza amaphakethe abe mancane», futhi zisebenza ezingqimbeni ezihlukene. I-MTU yesixhumi ikhawulela iphakethe ngalinye elithunyelwa idivayisi. I-MTU yomzila ikhawulela amaphakethe asebenzisa lowo mzila, futhi lokho kuvame ukuba yikho okukufunayo ngempela esikweni elilodwa le-VPN. Umkhawulo we-TCP MSS ushintsha lokho okuvunyelwana ngakho yizinhlangothi ezimbili, futhi awenzi lutho nge-UDP.
Izilawuli ezintathu ezibonakala njengenkinobho eyodwa
Zibeke ndawonye ngaphambi kokukhetha, ngoba ukukhetha umugqa ongafanele yikho okuchaza iningi lezeluleko ezingasebenzi:
| Control | Scope | What it cannot fix |
|---|---|---|
| Interface MTU | Every packet the device sends | Nothing, but it over-constrains unrelated traffic |
| Route MTU | Packets using that route | A send that the lookup never routes there |
| MSS clamp | TCP handshake on that path | UDP payload sizes and ICMP |
Ukwenza i-MTU ye-Ethernet yehle kuyo yonke imshini yinguqulo eluhlaza yalokhu kulungisa. Iyasebenza, futhi ijezisa noma iyiphi enye inkundla kusibungu, kuhlanganise nalezo izindlela zazo ezazilungile. Inani lomzila ngamunye liveza inhloso efanayo ngaphandle kwezindleko eziseceleni.
Ukuqhathanisa kuvumelekile kuphela kuthrafikhi ekhiqizwa yisibungu ngokwaso. Ukudlulisela iphakethe kuklayenti elinye kuhilela umzila walo kanye nesabelomali sangaphandle somhubhe, futhi imethrikhi yomzila kulesi sibungu ayidluli kuleso sikhala.
Xhuma isabelomali emzileni owinayo ekusesheni
Irekhodi yomzila ye-IPv4 eyisibonelo ibonakala kanje:
ip -4 route get 10.60.0.20
ip -4 route add 10.60.0.0/16 dev tun-office src 10.90.0.2 mtu 1380Funda irekhodi njengencazelo yenhloso, hhayi njengenani elizofakwa. Isandiso, idivayisi kanye nomthombo okhethiwe kufanele kuhambisane nokuhlelwa kwangempela, futhi inombolo kufanele ivele ebufakazini obumayelana nomzila ofihliwe, hhayi esihlokweni sebhulogi. I-MTU yomzila ikhawulela iphakethe le-IP langaphakathi, lokho akufani ne-TCP payload yamabhayithi angu-1380 noma iphakethe langaphandle elibethelwe elingamabhayithi angu-1380.
Bheka ukuthi ukusesha kuxazululwa kuphi ngempela ngaphambi kokufaka noma yini. Isibungu esinemikhawulo yenqubomgomo singahambisa indawo ethile ngaphakathi kwetafula elihlukile kune- main, futhi imethrikhi ekhona kuphela ku- main ayibonakali kuleso sicelo. Qhathanisa i- ip -4 route show table all nempendulo evela ku- ip route get, kuhlanganise umongo wophawu noma wesikhala samagama lapho imikhawulo iwasebenzisa. Uma lezi ezimbili zingavumelani, itafula eliphendulile yilona elidinga imethrikhi, hhayi lelo elibonakala lihlanzekile.
i-mtu akuyona i-mtu lock
Ngokuzenzakalela i-kernel isengabuyekeza i-MTU yomzila kusuka empendulweni ye-ICMP, yilokho okwenzelwe ukutholwa kwe-MTU yomzila. Ukwengeza i- lock kuyakumisa lokho. Kuyisinqumo esihlukile, akuyona indlela enamandla yokugcina inombolo efanayo, futhi ku-IPv4 kushintsha ukuphathwa okubhaliwe kwebhithi ethi «ungahlukanisi».
Ukukhiya kunengqondo uma usukalile umzila futhi ufuna inani lihlale linye noma yini efikayo. Kuwukusetha okuyisisekelo okubi lapho inethiwekhi ithumela impendulo yosayizi esemthethweni, ngoba i-kernel ayisakwazi ukuzivumelanisa futhi ukwehluleka kudlulela kwesinye isibonakaliso.
Uma i-ICMP ihlungiwe ndawana thize emzileni, asikho isilungiselelo somzila esikulungisayo lokho. Ukulungisa kungokwesihlungi, futhi i-MTU encane iyindlela yokugwema efihla iphutha langempela kuze kushintshe umzila olandelayo.
Isofthiwe yomhubhe yengeza izinkinobho zayo zosayizi
OpenVPN- mssfix ilungisa usayizi wesigaba se-TCP esimweni sayo esibhaliwe somhubhe we-UDP. Isebenza engxoxweni ye-TCP, ngakho akuyona enye indlela yokubhala i-MTU yomzila wesistimu yokusebenza, futhi ayikwazi ukusiza isevisi ye-UDP edebeselela ukuxoxisana.
Ungafaki i-MTU yomzila, ushintsho lwe-MTU yesixhumi kanye nomkhawulo we-MSS kuwindi elilodwa lokushintsha. Uma inkinga inyamalala ngeke wazi ukuthi yikuphi okwakubalulekile, futhi lokho okugcinayo kuzokhawulela ithrafikhi iminyaka ngaphandle kwesizathu esikhunjulwa umuntu.
Yenza kubuyiseke, bese ukuqinisekisa
Umnikazi wangempela womzila unquma ukuthi ushintsho luyasinda yini ekuxhumaneni kabusha. Iklayenti le-VPN elifaka umzila ngokuguquguqukayo livame ukuwukha kabusha ngaphandle kwemethrikhi yakho, futhi umyalo ip route add wokusebenza ngesandla ubonakala njengokulungisa okwehlulekile ngosuku olulodwa kamuva. Faka inani ekuhlelweni komphathi, futhi uma udinga ukuhlola kwesikhashana, qala ubhale umzila wangempela.
Hlola ngokuxhumana okusha okwenza umsebenzi owawumile, bese uqinisekisa ukuthi umzila wangasese ohlosiwe usanqoba futhi izindawo ezingahlobene azishintshanga. Xhuma umhubhe kabusha futhi ufunde umzila futhi, ngoba inani elinyamalalayo ekuxhumaneni kabusha akulona ukulungisa.
Uma ubufakazi bungahambisani noshintsho, susa ukweqa ngomphathi walo futhi ubuyisele izimiso zangempela zomzila esikhundleni sokuqeda umzila. Bese ubhala ukuthi ukalile ini, kumuphi umzila, ukuze umuntu olandelayo ahlukanise intuthuko yangempela nokuhlola okwashiywa kusebenza.