Pezani momwe DSN ikufunira kukhazikitsa malo obweretsera kwa imelo ya SMTP.
Munadabwapo Zotani Zomwe Zachitika pa Imelo Mudatumiza?
Ngakhale kungoyang'ana mwachidule pulogalamu ya SMTP mudzazindikira kuti pambali pa HELO, palinso EHLO, zomwe zimapangitsa seva Yowonjezera SMTP kulengeza mphamvu zake kuposa chiyero choyambirira. Chimodzi mwa izi ndi DSN. DSN? Kodi DNA ndi DDT sizikwanira?
Kunena kuti imelo ndi yosakhulupirika, kuti wina ayenera " ... kudyetsa seva yawo bwino, idya makalata anga ... " si zachilendo. Ndimachita izi ndekha. Komabe, palibe zifukwa zambiri zothandizira izi.
Kutumiza S tatus N otification wakhalapo kuyambira RFC 821 (kuyambira 1982). Mwamsanga pamene gawo la DATA la protocol ya SMTP latsirizidwa ndipo seva yalandira imeile yobereka ili ndi udindo wake. Ngati, pa chifukwa china, sichikhoza kufika kwa wolandirayo ayenera kuchibwezeretsa ndi chidziwitso cha cholakwika kwa wotumiza woyambirira. Izi zinachititsa ma imelo ena osadziwika.
Kupatula apo, msonkhano wachikale uwu umatanthauza kuti mwina muli ndi vuto lolakwika kapena mulibe kanthu komwe simukudziwa: imelo ikhoza kufika kapena ayi. Mauthenga olakwika nthawi zambiri anali othandiza monga mauthenga olakwika. Ndi imelo kukhala yofunika kwambiri izi sizikukhutiritsa (monga kale).
DSN Extensions kwa SMTP
RFC 1891 imapereka zowonjezera ku protocol ya SMTP yomwe imayenera kuwonetsa dongosolo lodalirika komanso logwiritsidwa ntchito kwambiri la DSN. Ili ndi ndondomeko yowonjezera ma command MAIL ndi RCPT (ngati izi sizikutanthauza kanthu kwa inu, werengani momwe SMTP ikugwiritsidwira ntchito ndikubweranso kuno).
Palibe ELO, Palibe Zosangalatsa
Choyamba, tiyenera kutsimikiza kuti seva imachirikiza DSN. Potero, timayenera kunena ELO ndi kumvetsera mwatcheru. Ngati akuyankha ndi DSN ena mwadongosolo mndandanda ife tingaganize kuti idzatha kutitumikira. Ngati ayi, ndiye ayi: tikhoza kuyesa seva ina kapena kungobwerera ku imelo popanda DSN. Mwachitsanzo (zowonjezera zanga ndi buluu, sevayo imatuluka yakuda):
220 larose.magnet.at ESMTP Sendmail 8.8.6 / 8.8.6; Sun, 24 Aug 1997 18:23:22 +0200
EHLO localhost
250-larose.magnet.at Hello localhost [127.0.0.1], ndikukondwera kukumana nanu
250-EXPN
VERB 250
250-8BITMIME
250-SIZE
250-DSN
250-ONEX
250-ETRN
250-XUSR
250 THANDIZO
Mwachimwemwe, pakati pa zinthu zina timapeza DSN.
DSN Sender Extensions
Lamulo lotsatira nthawi zambiri ndi MAIL FROM :. Ndi DSN, izi siziri zosiyana. Koma pali zina ziwiri zomwe mungapereke: RET ndi ENVID.
Chotsatira cha RET chinali m'malo momangika mwalamulo ku MAIL lamulo, koma likugwirizana pano komanso kulikonse. Cholinga ndicho kufotokozera momwe uthenga wanu woyambirira uyenera kubwezeretsedwera ngati mwalephera kubereka. Maganizo ovomerezeka ali OLZI ndi HDRS. Choyambirira chimatanthauza kuti uthenga wathunthu uyenera kuphatikizidwa mu uthenga wolakwika, HDRS imalangiza seva kuti ibwezeretse mutu wa makalata omwe alephera. Ngati RET sinafotokozedwe, ili pa seva choti nkuchita. Nthaŵi zambiri HDRS idzakhala mtengo wosasinthika.
ENVID kwenikweni ndi wa wotumiza monga iye kapena (kani) wake wothandizira imelo adzakhala yekhayo amene amatipanga ife mu vumbulutsoli . Cholinga chake ndi kuuza munthu amene atumizira mauthenga omwe amalembedwa. Maonekedwe a chidziwitsochi amachokera ku lingaliro la wotumiza. Sitidzagwiritsa ntchito ENVID mu chitsanzo chathu (malingaliro!):
MAU OCHOKERA: sender@example.com RET = HDRS
250 sender@example.com ... Kutumiza ok
Mwachiwonekere, ife tikungofuna kuti abwerere mmbuyo mu DSN yathu.
Zowonjezeredwa za DSN
RCPT TO: amapezanso gawo lachiyanjano chazowonjezera: DZIWANI ndi ORCPT.
DZIWANI mtima weniweni wa DSN. Ikuuza seva pamene kutumiza chidziwitso cha chidziwitso. Choyamba chofunika kwambiri ndi CHIYANI chomwe chimapangitsa kuti DSN isabwererenso kwa wotumiza. Izi sizingatheke popanda DSN. Ndiye pali CHINENERO, chomwe chidzakudziwitsani pamene makalata anu atsekedwa kumene akupita. KUCHITIKA NDI wothandizana naye (!): DSN idzafika ngati chiwopsezo chinachitika panthawi yobereka. Chotsatira chotsiriza ndi DELAY: udzadziwitsidwa ngati pali kuchedwa kosayembekezereka pakubereka, koma zotsatira zenizeni zobweretsa (kupambana kapena kulephera) sizinawonedwebe. KUSIYENERA kukhale kukangana kokha ngati kutchulidwa, zina zitatu zikhoza kuwonekera pa mndandanda, wopangidwa ndi chida. ZOKHUDZA NDI ZOTHANDIZA zimapangidwira gulu lolimba kwambiri (!), Ndikukuuzani (pafupifupi) vuto lililonse zomwe zinachitikira makalata anu.
Cholinga cha ORCPT ndicho kusunga wolandila uthenga wa email, mwachitsanzo ngati atumizidwa ku adiresi ina. Chotsutsana ndi njirayi ndi imelo ya mlandireyo ndi mtundu wa adiresi. Mtundu wa adiresi umabwera koyambirira, wotsatiridwa ndi semicolon ndipo potsiriza adilesi. Mwachitsanzo:
RCPT TO: support@example.com NOTIFY = FAILURE, DELAY ORCPT = rfc822; support@example.com
250 support@example.com ... Ololera ok (ndipepala)
Izi zikutsatidwa ndi DATA monga tikudziwira ndipo potsiriza, ndikuyembekeza, chidziwitso chodziwitsa anthu kukudziwitsani za kupambana.
Kodi DSN Imagwira Ntchito?
Zoonadi, kukongola konse ndi ulaliki kumangogwira ntchito ngati makalata oyendetsa makalata kuchokera kwa wotumiza kwa DSN thandizo. Tsiku lina iwo adzatero.