Kungani izindawo ezimbili ezine-subnet efanayo zingeyona LAN eyodwa

Amahhovisi amabili womabili asebenzisa 192.168.77.0/24, futhi othile uphakamisa umhubhe ukuze abe inethiwekhi eyodwa. Le nkulumo izwakala ilula futhi ifihla amadizayini amathathu ahlukene: ama-LAN amabili azimele ashayisanayo, ingxenye ye-Ethernet enwetshwe ngamabomu phezu kwe-WAN, kanye nohlelo lwe-proxy-ARP oluphendula izindawo ezikude. Ukuthi iyiphi onayo inquma ukuthi i-host yenzani ngephakethe, futhi impendulo ibonakala ngaphambi kokuba isango le-VPN ihlanganyele.

I-host inquma ngaphambi kwe-router

I-host enekheli elingu-192.168.77.10/24 iqhathanisa indawo okuyiwa kuyo ne-prefix yayo. Konke okungaphakathi kwale-prefix kusexhumweni oluqondile, ngakho i-host ixazulula ngqo ikheli lesigaba soxhumo lendawo okuyiwa kuyo. Konke okungaphandle kwayo kuyiswa ku-gateway ezenzakalelayo.

Leso sinqumo senzeka kusitaki se-host, hhayi emhubheni. Umzila owengezwe ku-gateway awukwazi ukusindisa iphakethe i-host engakaze ilithumele lapho.

Ngakho uma u-192.168.77.20 ekhona kuphela kwenye indawo, i-host yasendaweni iyabuza nge-ARP futhi ayitholi mpendulo. Ukuxhawulana kwe-VPN kungaba nempilo ephelele kuyilapho lokhu kwehluleka. Ukwehluleka kubonakala njenge-host efile hhayi njengenkinga yomzila. Ukubona lolu phawu kusindisa ihora lokulungisa umhubhe.

I-ARP iwumbuzo woxhumo lwasendaweni

I-ARP ibuza ukuthi ngubani ongumnikazi wekheli kulolu xhumo, futhi impendulo kufanele ivele entweni ezwa ukusakazwa. I-router engakolunye uhlangothi lomhubhe we-IPsec ayikuzwa lokho ngaphandle uma idizayini yenza izindawo ezimbili zibe yisizinda esisodwa sokusakaza.

Amadivayisi amabili anekheli elifanayo akwenza kube kubi kakhulu: ngisho isixazululo esiphumelelayo asikwazi ukusho ukuthi iyiphi ephendulile.

Ukuhlanekezelwa kwamakheli akuyona iphutha lomzila futhi awekho umzila owulungisayo. Noma izindawo zibhalwa kabusha ngezinombolo zibe ama-prefix ahlukene, noma ngamabomu ziba yisizinda esisodwa sesigaba soxhumo.

Ingxenye enwetshiwe ithwala ama-frame, hhayi imizila

Umhubhe othwala i-Ethernet futhi oxhunyiwe emabhulohweni wenza izindawo zombili zibe yingxenye yesizinda esisodwa sesigaba soxhumo. Ukusakazwa kwe-ARP kufinyelela kolunye uhlangothi, futhi ibhuloho ngalinye lifunda ukuthi yimaphi amakheli e-MAC akhona kuphi. Imibhalo yebhuloho le-Linux ichaza lowo mngcele wokudlulisa osekelwe ku-MAC.

Lapha i-gateway ekude ayidlulisi nhlobo phakathi kwama-subnet amabili afanayo. Ama-frame adlula engxenyeni engezansi ezidlulisela yona i-IP, kuyilapho amabhuloho enweba ingxoxo ye-Ethernet.

Intengo iwumkhakha omkhulu womthelela. Ukugcwala kwezindawo ezingaziwa, imijikelezo, ukwabiwa kwe-DHCP nokuhlanekezelwa okuhlukile konke kudinga uhlelo olulodwa oluhlanganisa izindawo zombili. Uma i-WAN iwa, ama-host alahlekelwa ukuthunywa akubona njengakwasendaweni. Ukuhlunga ebhulohweni nemithetho ye-VLAN kungakhawulela okudlulayo, kodwa ukuthwala akusathembisi ukuthi yonke ingxenye yokulawula yasendaweni izofika.

I-proxy ARP iwudizayini wesithathu

I-router ingaphendula i-ARP yekheli elikude bese idlulisela khona. Lokho kwenza i-host ekude ibonakale isexhumweni oluqondile kumthumeli ngaphandle kokunweba isizinda sokusakaza.

Ithuluzi elincanyana kunokwakha amabhuloho: lincike ekudluliseni, emizileni yokubuya nasekubeni nomnikazi ocacile wekheli ngalinye.

Futhi akwenzi amaphrothokholi angenalo i-IP adluleke, futhi akukhiqizi isizinda sokusakaza se-Ethernet. Kusebenzise uma imfuneko iyilokho kufakwa esikhundleni, hhayi njengesinqamuleli sokuhlanekezela okuhlehlisiwe.

Khetha ngokwemfuneko, bese uqinisekisa

Ekufinyeleleni okujwayelekile kwezinhlelo phakathi kwamahhovisi, ama-prefix ahlukene nemizila ecacile kunikeza umngcele ocace kakhudlwana. Yakha ibhuloho uma imfuneko iwukusondelana kwesigaba soxhumo ngempela. Bhala kabusha izinombolo uma isizathu esisodwa se-prefix eyabiwe iwukuthi akekho osakwenzile lokho.

Qinisekisa ukuthi iwuphi umdizayini onawo ngempela ngokubuza i-host ukuthi yenzani ngendawo okuyiwa kuyo:

ip route get 192.168.77.20
ip neigh show 192.168.77.20

Umphumela osexhumweni oluqondile onomkhondo womakhelwane ohlulekile ukhomba indlela yesigaba soxhumo engekho. Umphumela we-via ubiza i-gateway futhi uhambisa umbuzo emzileni. Ebhulohweni, hlola isizindalwazi sokudlulisa ukubona ukuthi i-MAC ifundwe ngomhubhe yini. Konke okuphumayo kunciphisa umbuzo womdizayini esikhundleni sokuqala kabusha.