IProtokholi yokuThumela iMeyili elula (SMTP) ngumgaqo-nkqubo wokunxibelelana oqhelekileyo wokuthumela imiyalezo ye-imeyile kumanethiwekhi oshishino kunye ne-Intanethi. I-SMTP yaqale yaveliswa ekuqaleni kwee-1980 kwaye ihlala enye yeeproducts ezifunwa kakhulu emhlabeni jikelele.
I-software ye-imeyile isebenzisa ngokubanzi i-SMTP yokuthumela kunye nokuba yi-Post Office Protocol 3 (POP3) okanye i-Intelligence Access Protocol (IMAP) yokufumana i-imeyile. Naphezu kobudala bayo, akukho nenye indlela ekhoyo kwi-SMTP ekhoyo kusetyenziso oluqhelekileyo.
Indlela SMTP isebenza ngayo
Zonke iiprogram zeklayenti zamakhasimende zanamuhla zixhasa iSTPTP Izicwangciso ze-SMTP ezigcinwe kumxhasi we-imeyile ziquka idilesi ye - IP yomncedisi we-SMTP (kunye needilesi ze-POP okanye i-IMAP iseva ngokufumana ii-imeyile). Abaxhasi abasekelwe kwiwebhsayithi banamathele idilesi yomncedisi we-SMTP ngaphakathi koqwalaselo lwabo, ngelixa abathengi be-PC banikezela izicwangciso ze-SMTP ezivumela abasebenzisi ukuba bachaze umncedisi wabo ozikhethelayo.
Iseva yangasese yeS SMTP ingazinikezelwa ekukhonzeni i-imeyile yendlela kuphela kodwa ihlala idibene kunye ne-POP3 kwaye ngamanye amaxesha imisebenzi ethile yomseli weproxy .
I-SMTP isebenza phezulu kwi- TCP / IP kwaye isebenzisa inombolo ye- TCP yefowuni ye- 25 yokuxhumana ngokuqhelekileyo. Ukuphucula i-SMTP kunye nokunceda ukulwa nogaxekile kwi-Intanethi, amaqela amacandelo ayenze i-TCP port 587 ukuxhasa iinkalo ezithile zeprotocol. Iinkonzo ezimbalwa ze-imeyile zeWebhu, njengeGmail, sebenzisa i-port ye-TCP engafanelekanga ye-465 ye-SMTP.
Imiyalelo ye SMTP
Umgangatho we-SMTP uchaza isethi yemiyalelo - amagama eentlobo ezithile zemilayezo ezithumela abathengi kwi-imeyile yeposi xa becela ulwazi. Imithetho esetyenziswa ngokuqhelekileyo yile:
- I-HELO ne- EHLO - imiyalelo eqala iseshoni entsha yeprotocol phakathi kwabaxhasi kunye nomncedisi. Umyalelo we-EHLO ucela ukuba baphendule naluphi na ukwandiswa kweS SMTP oluxhasayo
- I-MAIL - umyalelo wokuqalisa ukuthumela umyalezo we-imeyili
- Umyalelo we-RCPT ukubonelela idilesi enye ye-imeyile yommkeli womyalezo okhoyo ngoku ulungiselelwe
- Umyalelo we- DATA obonisa ukuqala kokuthunyelwa komyalezo we-imeyile. Lo myalelo uqala uchungechunge lomyalezo omnye okanye ngaphezulu olandelayo oqulethe umyalezo womyalezo. Umyalezo wokugqibela ngokulandelelana awunanto (ophethe kuphela ixesha (.) Njengelungelo lokuphelisa) ukubonisa ukuphela kwe-imeyile.
- I-RSET- ngelixa kuthunyelwa i-imeyile (emva kokukhupha umyalelo we-MAIL), okanye ukuphela kokunxibelelana kwe-SMTP kungasetha kwakhona umnxibelelwano xa kudibana nephutha
- I-NOOP - umyalezo ongenalutho ("akukho msebenzi") owenzelwe njengomhlobo we- ping ukujonga ukuphendula kwesinye isiphelo seseshoni
- I-QUIT - iphelisa iseshoni yeprotocol
Ummkeli wale miyalelo uyaphendula ngeempumelelo okanye iinombolo zekhowudi zokuhluleka.
Iingxaki kunye neSTPTP
I-SMTP ayikho imisebenzi ekhuselweyo yokukhusela. I-spammers ye-Intanethi iyenziwe ukuba isebenzise i-SNMP esikhathini esidlulileyo ngokuvelisa inani elikhulu le-imeyli elingenayo i-junk kwaye liye lithunyelwe nge-SMTP iseva. Ukukhuselwa kogaxekile kuphuculwe ngaphezu kweminyaka kodwa ayikho into ekhohlisayo. Ukongeza, i-SMTP ayikuthinteli ugaxekile ekumiseni (nge-MAIL umyalelo) inkohliso "Ukusuka:" iilesi zeeyile.