I-ping nge-VPN: kungani imithetho yempendulo ye-echo yehluleka indlela yokubuya

Thumela i-ping ku-host nge-VPN futhi isicelo siphuma ngohlobo olulodwa lwe-ICMP siphinde sibuye ngolunye, lokho kwanele ukudida noma yimuphi umthetho obhalwe ngezimbobo. Ekushintshisaneni kwe-echo awekho umbobo wesevisi wendawo okufanele ukopishwe kumthetho wokubuya, futhi isihlungi esilindele ukulingana sizolahla impendulo ngesikhathi isicelo sidlula ngaphandle kwesithiyo. Ukulungiswa kuqala ngokufunda iphakethe njengoba linjalo ngempela, bese kuthi ngemva kwalokho kunqunywe ukuthi iyiphi imingcele emzileni eyenza isinqumo. Ngokuvamile izingqimba ezimbili ziyasebenza kanti eyesithathu ilahla impendulo ngokuthula. Izigaba ezingezansi ziyahlukanisa ngokulandelana iphakethe elihlangana nazo.

Iphakethe lishintsha uhlobo, hhayi umbobo

Isicelo se-echo i-ICMP uhlobo 8, ikhodi 0, futhi sithwala isihlonzi kanye nenombolo yokulandelana. Impendulo inguhlobo 0, ikhodi 0, ngesihlonzi nokulandelana okufanayo, futhi iziphetho ze-IP zishintshiwe. Lezi zinkundla zichazwa yi-RFC 792, futhi isihlonzi yiso esivumela umthumeli ukuthi ahlobanise izimpendulo neziecelo zakhe.

Lokho okungekho kubalulekile ngokufanayo: akukho khanda le-TCP noma le-UDP, ngakho-ke akukho mbobo okufanele uvunyelwe. Umthetho oqamba umbobo wempendulo ye-echo uchaza iphakethe elingasoze libe khona. Leli yiphutha elivame kakhulu kumathikithi e-ping e-VPN. Umthetho ubonakala uqondile, awusebenzi kunoma yini, futhi ushiya ukwehluleka khona lapho kwakukhona.

Izimo ezintathu zinquma iphakethe

Uma i-ping iqonde ku-host ekude ku-LAN, isicelo kufanele sidluliswe isango. Uma iqonde ikheli elingelesango uqobo, siphela emzileni wokufaka wendawo. Uma isango uqobo luqala i-ping, iphakethe liqala emzileni walo wokuphuma futhi aliyi nhlobo esinqumweni sokudluliswa.

Lezi zimo ezintathu zinamaketanga emithetho nezikhonzi ezihlukile, futhi ukuzithatha njengenye yikho okuyisizathu sokuthi «i-firewall ivumela i-ICMP» kusengaba ne-ping ehlulekile. Umhubhe wangaphandle uyisimo sesine: ukuvumela isilaleli se-VPN akuvumeli ngokuzenzakalela isicelo sangaphakathi esikhishwe, futhi imvume yangaphakathi ayisho lutho mayelana nokuthi umhubhe wangaphandle uyasebenza yini.

Izihlungi ezinesimo nezingenaso ziphatha impendulo ngendlela ehlukile

I-firewall enesimo eyabona isicelo siphuma ingahlobanisa impendulo naleyo kugeleza bese iyivumela ngaphandle komthetho wesibili. Isihlungi esingenasimo asinayo leyo nkumbulo, ngakho-ke indlela yokubuya idinga imvume yayo ecacile, ngokushintshwa komthombo nendawo.

Hlola ukuthi umkhiqizo usebenzisa yiphi imodeli ngempela ngaphambi kokubhala noma yini. Umthetho wesicelo se-echo awumbo ngempela umbo lwempendulo ye-echo, futhi umkhiqizo olandelela imibuzo ye-ICMP usengasebenzisa inqubomgomo ehlukile kuzimpendulo ezifika kwesinye isixhumanisi.

Khakha lokho okuvumelayo. Ukuvumela yonke impendulo ye-echo ivele noma kuphi akufani nokuqedela ukuhlobana okunesimo, futhi inombolo yohlobo ayiqinisekisi umthumeli.

Ukuhumusha kushintsha nesihlonzi

Uma ukuhumusha komthombo kwenziwe ngamabomu, i-tuple ekugcineni okukude ayihambisani naleyo ethunyelwe yiklayenti. I-NAT ingahumusha isihlonzi sombuzo we-ICMP kanye namakheli, ngakho-ke ukuphoqa ukuthi inombolo efanayo ivele ezinhlangothini zombili kudala ukungafani okungamanga.

Esikhundleni salokho hlobanisa nemephu ebikwa yisihumushi. Isihumushi esibhala kabusha isihlonzi ngeke sigcine inombolo eyaqoshwa yiklayenti lakho, ngakho-ke thatha imephu njengobuqhezu hhayi inombolo. Bese landelela isicelo esisodwa esibonakalayo emzileni wonke: qinisekisa ukuthi sifika endaweni ngomthombo olindelekile, qinisekisa ukuthi indawo yathumela impendulo, landelela umzila wokubuya waleyo mpendulo, futhi qinisekisa ukuthi iklayenti iyitholile esikhundleni sokubuka isibali sesango sikhuphuka.

Ungahlanganisi amaphutha e-ICMP kunqubomgomo ye-echo

Umlayezo othi «ukuhlukaniswa kuyadingeka» osetshenziswa ukuthola i-MTU yomzila awuyona impendulo ye-echo, futhi umthwalo wawo ucaphuna iphakethe elikubangele. Imvume ye-echo kuphela elahla lawo maphutha ngokuthula iguqula inkinga yosayizi ibe ukuxhumana okulengayo, okuphambene nokusiza.

Ukuqapha okufanayo kuyasebenza emindenini yamakheli. I-ICMPv6 isebenzisa izinhlobo zemilayezo ezihlukile futhi ithwala imisebenzi ebalulekile i-IPv4 engenayo, ngakho-ke ukukopisha lezi zinombolo kumthetho we-IPv6 kumane nje kuyiphutha.

Uma ukushintshisana kwe-echo kusebenza, hlola uhlelo lokusebenza lwangempela ngokwahlukile. I-ping ephumelelayo ifakazela ukuhamba nokubuya kophrotokholo olulodwa ngosayizi oyedwa oluya endaweni eyodwa, futhi akusona imvume yokucabanga ukuthi i-HTTPS, i-SMB noma okunye ukugeleza kuvunyelwe.