Wayar da ke kan hotspot ɗinka mai gada tana samun adireshinta da ƙofarta daga wani wuri, kuma wannan ba hanyar da ba ta dace ba ta Pi ba ce. Canja hanyar da ba ta dace ba ta Pi yana canja inda Pi ke aika nasa zirga-zirgar. Wayar tana ci gaba da amfani da ƙofar da aka gaya mata, kuma idan wannan ƙofar tana kan LAN mai nisa, firamminta suna wucewa gadar kawai. Masu amfani biyu, shawarwari biyu. Rabar da su yana bayanin yawancin rahotannin hotspot marar intanet yayin da Pi kansa yake lafiya.

Na'urori biyu, shawarwarin ƙofa biyu daban-daban

Pi yana da tarin IP nasa da hanyar da ba ta dace ba tasa. Wayar tana da tarin IP nata da hanyar da ba ta dace ba tata.

ConsumerWho chooses its gatewayWhat carries the traffic
Phone on the bridged APThe remote LAN router, delivered in its client configurationAn Ethernet frame toward that router crosses the AP and TAP bridge
Pi's encrypted connectionThe travel uplink's route toward the VPN peerThe Pi sends its own outer transport packets over the underlay

Wannan tebur shine dukan tsari. Ƙofar wayar adireshi ce a kan LAN mai nisa, kuma ana tura firamminta a Layer 2 zuwa wannan na'urar sarrafa hanya. Hanyar da ba ta dace ba ta Pi ta shafi jigilar waje ta Pi kanta, wadda dole ta isa abokin VPN ta hanyar uplink ɗin tafiya.

Gada tana tura firamai, ba ta sarrafa fakiti

Gadar Linux tana tura firamai na Ethernet bisa MAC ɗin manufa, kuma wannan ne kawai abin da take yi tsakanin tashoshinta. Frames ɗin wayar da aka yi wa MAC ɗin na'urar sarrafa hanya mai nisa adireshi ana canza shi zuwa tashar TAP kuma yana wucewa ramin ba tare da taɓa teburin sarrafa hanya na Pi ba. Shi ya sa hanyar da ba ta dace ba ta Pi da ta lalace za ta iya barin wayar tana aiki, kuma shi ya sa wadda ta dace ba za ta iya gyara wayar da aka ba ta ƙofar da ba daidai ba.

TAP tana ɗaukar firamai na Ethernet kuma tana iya zama tashar gada. TUN tana ɗaukar fakitin IP kuma ba za ta iya ba. Idan ƙirar ka ta maye gurbin ɗaya da ɗayan, gadar ba gada ba ce kuma sauran wannan ba ya aiki.

Yanke shawara wanda ke ba da lease ɗin wayar

Zaɓin DHCP 3 shine zaɓin na'urar sarrafa hanya, kuma yana gaya wa abokin ciniki wace ƙofa za ta yi amfani da ita don subnet ɗinsa. Lokacin da uwar garken DHCP na LAN mai nisa ita ce kawai mai rarrabawa, wayar tana samun ƙofar nesa kuma ƙirar tana daidaita. Lokacin da wani abu a gefen tafiya ya amsa farko, wayar tana samun ƙofar gida, zirga-zirgarta ta intanet tana fita ta uplink ɗin tafiya, kuma zirga-zirgarta zuwa LAN mai nisa ba ta da wata hanya kwata-kwata.

Gudanar da mai rarrabawa ɗaya don wannan yankin watsa, kuma rubuta abin da yake bayarwa.

Pi lamari ne daban koda yana karɓar adireshi daga wannan lease ɗin. Yanke shawara da gangan ko ya kamata ya shigar da hanyoyin da lease ɗin ke bayarwa, domin hanyar nesa da aka shigo da ita tana iya jawo jigilar VPN ta Pi cikin ramin da yake ƙoƙarin kiyaye rai. Da systemd-networkd wannan shawara ita ce UseRoutes= a cikin sashin DHCP; da dhclient shine zaɓin routers a cikin jerin buƙatun.

Kiyaye uplink a waje da LAN ɗin gada

Interface ɗin da ke ɗaukar haɗin VPN na waje na Pi bai kamata ya zama tashar gada ba. Idan ya zama, ana canza jigilar sirrin zuwa LAN ɗin da aka faɗaɗa kuma ramin yana ɗaukar fakitin waje nasa, wanda ke gazawa ta yadda yake kama da asarar fakiti maimakon madauki. Kiyaye ikon AP da tallafin gada a bayyane kuma. Interface mara waya a yanayin station yawanci ba zai iya zama tashar gada ba, domin kan 802.11 ba shi da wuri don adireshin MAC na biyu da gada ke buƙata.

Ayyana yankin watsa da aka faɗaɗa, tsarin adireshi ɗaya, da tacewar firam ɗin da kake so da gaske. Ba da izinin mai sauraron VPN a Pi ba ya ba kowane abokin ciniki na gada damar shiga ayyukan gudanarwa na Pi. Waɗannan dokoki ne daban, kuma ɗaukar su a matsayin ɗaya shine yadda hotspot ke zama buɗaɗɗen ƙofa a hankali.

Gwada abubuwa huɗu daban idan ya lalace

Lokacin da wayar ba za ta iya isa LAN mai nisa ba, abubuwan lura huɗu suna raba musabbabin. Gudanar da su a wannan tsari kuma tsaya a farkon wanda ya kasa.

ip route show default
bridge link show
ip -4 neigh show dev br0
tcpdump -ni br0 arp or icmp

Fara da lease ɗin: shin wayar tana riƙe adireshi da ƙofa a subnet ɗin nesa? Sannan duba gadar, kuma tabbatar tashar AP da tashar TAP duka suna turawa. Sannan karanta teburin maƙwabta, domin shigarwar da ba a warware ba don na'urar sarrafa hanya mai nisa tana nufin firamai suna fita babu abin da ke amsawa. A ƙarshe kalli firamai akan gadar yayin da wayar ke ping, wanda ke gaya maka ko aƙalla laifin yana ƙasan IP.

Rubuta wace na'ura ce ta mallaki kowace hanyar da ba ta dace ba idan ka gama. Layi ɗaya na takardu yana mai da fita ta gida da ta nesa shawarar abokin ciniki da gangan, kuma tunatarwar gadar ta cancanci a riƙe kusa da ita.

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