Iphakethe le-IPv6 likhulu kakhulu: kungani ukudluliswa okukhulu kwe-VPN kuma

I-ping iyasebenza, isiphequluli silayisha ikhasi elincane futhi ukudluliswa kwefayela kuyama, konke nge-IPv6 kumhubhe ofanayo. Leli phethini ngokuvamile lisho ukuthi umthumeli akazange afunde usayizi wangempela wendlela, hhayi ukuthi umhubhe uyanensa. I-IPv6 ilindele ukuthi amarutha abike inkinga ngomlayezo we-Packet Too Big, futhi ukufakwa kwesikhwama kunezela umthwalo ngaphambi kokuba iphakethe lifinyelele inethiwekhi yangaphandle. Uma lowo mlayezo uhlungiwe, umthumeli uyaqhubeka ephinda usayizi ongenakudlula.

Izicelo ezincane, ukuma okukhulu

Umhubhe usonga iphakethe ngalinye kunhloko enye, ngakho usayizi osebenzisekayo ngaphakathi mncane kunosayizi ngaphandle. Iphakethe elikalwe ukuxhumana komzimba ngaphambi kokufakwa kwesikhwama liba likhulu kakhulu ngemuva kwalokho. Amarutha e-IPv4 angahlukanisa endleleni, kuyilapho amarutha e-IPv6 engakwenzi lokho egameni lomthumeli, ngakho umthumeli kufanele azilungisele yena. Futhi lokho kuzilungisa kuncike ngokuphelele ekutholeni impendulo.

Umlayezo owodwa olahlekile wanele ukukhiqiza uphawu olujwayelekile: ukuxhawulana nezimpendulo ezincane kuyaphumelela, futhi uhlu lwedirectory noma ukulayisha kuyama endaweni efanayo njalo. Abasebenzisi bakuchaza njenge-VPN enensayo, futhi amalogi awakhombisi lutho olungalungile ekuqinisekiseni. Kokubili ukuqaphela kuqondile futhi akukho okukhomba indawo yephutha.

I-Packet Too Big iyimpendulo, hhayi ithrafikhi

Umlayezo we-ICMPv6 Packet Too Big uthwala usayizi ongamukelwa yigxathu elilandelayo, futhi umthumeli uwusebenzisa ukwehlisa isilinganiso sakhe. Ukuwuhlunga kufana nokususa uphawu lomgwaqo bese usola abashayeli. Umthetho olahla yonke i-ICMPv6 ubukeka uqinile kodwa uphula ukutholakala kwendlela kukho konke ukuxhumana okukudingayo. Umlayezo ulwazi lokulawula mayelana nendlela, hhayi umthwalo wohlelo lokusebenza.

Ukuhlunga okukhethiwe kusenengqondo. Izicelo ze-echo nokutholakala komakhelwane zidlala indima ehlukile kumilayezo yephutha, futhi inqubomgomo ingaziphatha ngendlela ehlukile. Landela imihlahlandlela yokuhlunga ebhaliwe yepulatifomu esikhundleni sokwamukela noma ukulahla yonke iphrothokholi, ngoba i-RFC 8201 ichaza ukuthi leyo mpendulo ihamba kanjani ekutholakaleni.

Hlola zombili izinhlobo zamakheli ngokwehlukana

Hlola i-IPv6 ngokwayo, ngoba ukudluliswa kwe-IPv4 okuphumelelayo akufakazi lutho mayelana nendlela ye-IPv6. Bese ubamba imilayezo yokulawula ngenkathi ukudluliswa okukhulu kuma. Womabili amarekhodi ndawonye akhombisa ukuthi impendulo iyaphuma noma afakazela ukuthi ayizange ifike.

ping -6 -M do -s 1400 host.internal
ip -6 route get 2001:db8:2::10
sudo tcpdump -ni any 'icmp6 and ip6[40] == 2'

I-probe ithumela iphakethe elinebhithi ye-do-not-fragment esethiwe futhi ibika usayizi lapho yehluleka khona, yilowo nombolo okufanele umhubhe uyihambise. Umbuzo wendlela usho isixhumanisi esizothwala indawo ekuyiwa kuyo, ngakho uyazi ukuthi iyiphi i-MTU yokuxhumana esebenzayo. Ukubamba kuhlunga i-ICMPv6 uhlobo 2, umlayezo we-Packet Too Big, futhi kukhombisa ukuthi ufinyelela kule host noma cha. Uma umlayezo uvela ekubambeni futhi ukudluliswa kusama, umthumeli uyawushaya indiva, okuhambisa uphenyo ekuqoqweni hhayi kunethiwekhi.

Shintsha usayizi womhubhe ngemuva kobufakazi kuphela

Ukwenyusa i-MTU yomhubhe kunganomphumela wokufihla umlayezo ohlungiwe futhi kususe uphawu, kodwa ngezindleko zomthwalo owengeziwe kuphakethe ngalinye. Lokho kuwukugwema hhayi ukuxilonga, futhi kufanele kulandele ukubamba esikhundleni kokukushintsha. Inani eliphansi ngokungenangqondo nalo alilimazi lutho olubonakalayo, yingakho lihlala emikhawulweni iminyaka. Lishintshe ngamabomu, bhala inani, futhi uphawule ukuthi yikuphi ukulinganisa okwalifanelekela.

Uma ulawula isango, hlola umthetho olahla umlayezo esikhundleni sokuvala isivikelo somlilo. Umthetho owodwa olungisiwe mncane kunokukhululwa kwenqubomgomo futhi kulula kakhulu ukuwuvikela kamuva. Umqondo ofanayo usebenza kuzikhathi zokuvala: akukhona konke ukuma okuyinkinga yosayizi, futhi ukubamba yikho okwehlukanisa kokubili.