Ukuthunyelwa kwe-imeyili kuyahluleka lapho i-VPN ixhuma: thola isigaba

I-imeyili ebesisebenza isikhathi sasekuseni sonke iyama ngaso leso sikhathi lapho umhubhe unyuka, futhi umuzwa wokuqala ukuthi uphinde ubhale iphasiwedi. Lowo muzwa udlula umbuzo owusizo kakhulu: ingabe iklayenti lafika kuseva, futhi lafika lapho lalingase linikeze imininingwane yokungena? Isikhathi sokulinda, iphutha lesitifiketi kanye nempendulo yokwenqaba kungukuhluleka okuthathu okuhlukene, futhi okwesithathu kuphela okuhlobene ne-akhawunti. Hamba ezigabeni ngokulandelana, bese i-VPN iba uguquko ongaluhlola esikhundleni somsolwa obekwa icala.

Isigaba 1: hlukanisa ukuhluleka ngaphambi kokuthinta imininingwane yokungena

Funda iphutha elenziwe uhlelo ngempela, bese ulibeka kwelinye lamabhakede amathathu. Isikhathi sokulinda noma ukusethwa kabusha koxhumano kusho ukuthi indlela ye-TCP yehlulekile; iphutha le-TLS noma lesitifiketi kusho ukuthi indlela yasebenza kodwa ukuxhawulana kwezandla akuzange kusebenze; impendulo ye-SMTP enekhodi isho ukuthi iseva ye-imeyili iphendule futhi yathatha isinqumo. Ibhakede ngalinye likhomba kumuntu ohlukile onomthwalo.

Kufanelekile ukwehlukanisa amabhakede ngoba izilungiso ziyaphikisana. Ukwelula isikhathi sokulinda akusizi lapho iseva inqaba umthumeli, futhi ukushintsha iphasiwedi akwenzi lutho lapho indlela ivaliwe. Ikhodi yempendulo ingubufakazi obaluleke kakhulu ohlwini, ngoba ifakazela ukuthi wonke umucu wokuthutha wasebenza nokuthi inkinga ingeyenqubomgomo noma ubunikazi. Gcina umbhalo oqondile, kuhlanganise nanoma iyiphi ikhodi yesimo enwetshiwe, ngaphambi kokuzama futhi.

Yima lapha uma ungakwazi ukuphinda ukuhluleka ngaphandle kwe-VPN. Inkinga ebonakala kuhlelo olulodwa kumshini owodwa ayikabi inkinga yenethiwekhi.

Isigaba 2: qinisekisa iphuzu lokugcina kanye nemodi ye-TLS

Ukuthunyelwa kwemiyalezo kuyisevisi yayo, akuyona into efanayo nokudluliswa kusuka kuseva kuya kuseva. Qinisekisa igama lomsingathi, imbobo kanye nemodi ye-TLS emibhalweni yomhlinzeki yokuthumela, ngoba imbobo eyaziwayo ebolekwe kokunye ukuhlelwa kwe-imeyili akubona ubufakazi. Imbobo engu-587 ilindele ukubingelela ngombhalo ocacile bese ilandelwa yi-STARTTLS, kanti imbobo engu-465 ilindele i-TLS kusukela kubhayithi yokuqala.

openssl s_client -connect smtp.example.com:465 -servername smtp.example.com -quiet
openssl s_client -starttls smtp -connect smtp.example.com:587 -servername smtp.example.com -quiet
nc -vz smtp.example.com 587

Ukwenza ukuhlola okungalungile kokubili kunguphutha oluqondile olwenziwa iklayenti lapho lilungiselelwe enye imodi. Uma ukuhlola kwe-TLS okusobala kukhala ku-587, noma ukuhlola kwe-STARTTLS kwehluleka ku-465, imbobo nemodi azihambisani. Lungisa imodi eklayentini esikhundleni sokuvala ukuqinisekiswa kwesitifiketi, okuvamise ukuguqula iphutha lokuhlelwa kube ukuxhumana okungaqinisekisiwe. Lokhu kwehlukanisa kudala ngokwanele ukuba kube umgangatho: i-TLS esobala embotsheni engu-465 iyilungiselelo elichazwe ku-RFC 8314.

Iphutha lesitifiketi lapha ulwazi hhayi isithiyo. Lisho ubunikazi obesethulwa yiseva kanye nobunikazi obekulindelekile iklayenti, futhi kokubili kungalungiswa ngaphandle kokwenza ukuxhumana buthaka.

Isigaba 3: qhathanisa izindlela ngaphandle kokushintsha i-akhawunti

Gcina iphuzu lokugcina, i-akhawunti kanye nezilungiselelo zeklayenti zingashintshi bese ushintsha indlela kuphela. Thumela kanye lapho umhubhe uphansi nokanye lapho uphakeme, futhi bhala umzila kanye nekheli lomthombo iseva ebingalibona. Uma ukuhluleka kulandela indlela, ukuhlukanisile; uma kulandela umshini, awukuhlukanisanga.

ip route get smtp.example.com
curl -v --ssl-reqd --url smtp://smtp.example.com:587 --user "$SMTP_USER" \
  --mail-from [email protected] --mail-rcpt [email protected] --upload-file msg.txt

Umhubhe ogcwele ushintsha ikheli lomthombo umhlinzeki alibonayo, futhi abanye abahlinzeki baphatha umthombo ongaziwa ngokuqinile kunephasiwedi engaziwa. Leso yisinqumo senqubomgomo ohlangothini lwabo, futhi kungaba uhlu olumpunga, umkhawulo wejubane noma ukuvalwa. Ungajwayeli kusuka kumhlinzeki oyedwa ukuya kubo bonke, futhi ungacabangi ukuthi umthetho we-NAT ongekho uchaza konke ukuhluleka. Umbhalo we-curl ukhombisa ukuthi yisiphi isigaba esihlulekile ngisho nalapho ilogi yohlelo uqobo ingakukhombisi.

Uma umhubhe kufanele uthwale ithrafikhi ye-inthanethi, kokubili ukuhamba kwayo kanye nenqubomgomo yokuphuma kwayo kufanele kuvume le ndawo. Umhubhe othwala izindlela zangasese kuphela ushiya ukuxhumana kwe-imeyili endleleni yasendaweni, okuwukuhambisa okunye.

Isigaba 4: thumela umyalezo owodwa ongenabungozi bese ubhala impendulo

Lungisa isigaba esihlulekile, bese uthumela umyalezo owodwa ongenabungozi ngohlelo olufanayo hhayi ngekhasi le-webmail. Lokho okuhlolayo yindlela yokuthumela yohlelo uqobo, kuhlanganise nezilungiselelo ezigciniwe kanye nemodi ye-TLS. Isikhathi se-webmail asifakazeli lutho ngalokho.

Bhala impendulo, imbobo, imodi ye-TLS kanye nendlela oyisebenzisile, ukuze umuntu olandelayo akwazi ukuphinda umphumela. Isiphequluli esisebenzayo kanye nesithonjana se-VPN esiluhlaza kungukubona mayelana nezinye izinto. Uma umyalezo ufika, umsebenzi osele ukwenza lokho kulungiselelwa kube okuzenzakalelayo kumshini ngamunye othumela ngale akhawunti.

Uhlu lokuhlola luphelela lapho ungangasho isigaba esihlulekile, imbobo nemodi ye-TLS esetshenziswa iklayenti, indlela umyalezo oyihambile kanye nempendulo eyebuyiselwe yiseva. Lezi ziqiniso ezine ziguqula inkinga engacacile yebhokisi lokuphuma ibe ushintsho umuntu angalubuyekeza.