Baocao Tong Hop

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  • 1. NHM 8
  • 2. Cc thnh vin trong nhm
    • Phm Quang Chc
    • V Vn Hon
    • Nguyn Anh Thi
    • Lu nh Trung
    • Phm S Vinh
  • 3. 15.2 Sendmail
    • L mt chng trnh phc tp c thit k cho hu ht cc h iu hnh vi m ngun bao gm hng ngn dng lnh C.
    • c chy vi quyn ca ngi qun tr h thng do chng trnh phi c quyn ghi vo hp th ca ngi s dng.
  • 4. H thng E-Mail thng trng gm 3 phn chnh:
    • Mail User Agent(MUA): l chng trnh m ngi dng s dng c v gi email. N c email c gi vo mailbox ca ngi dng v gi email ti MTA gi n ni nhn.
    • Mail Tranfer Agent (MTA): hot ng c bn ca n ging nh mt "mail router" n nhn email t cc MUA hay t mt MTA khc, da vo thng tin trong phn header ca email n s a ra x l ph hp vi email , sau email s c gi n mt MDA ph hp gi email .
    • Mail Delivery Agent (MDA): nhn e-mail t MTA v thc hin vic gi email n ch thc s.
  • 5.
    • V d sau c th gip bn c bn hiu c ba thnh phn MUA, MTA, MDA lm vic vi nhau nh th no trong mt h thng Mail Server
  • 6.
    • User trn host1.uiuc.edu dng mt chng trnh MUA(pine, elm ..) gi mail cho mt user khc trn host2.uiuc.edu, mail u tin c gi n mt MTA (sendmail) trn host1.uiuc.edu (localhost).
    • MTA kim tra mail v bit c a ch ch ca email , MTA c config n bit lm th no gi c e-mail n ch v n s gi email n mt MDA n thc hin iu (vi sendmail th mt MDA c tch hp sn trong n).
    • MDA s kt ni vi MTA trn host2.uiuc.edu v gi email ti
    • MTA trn host2.uiuc.edu kim tra mail nhn c v xc nh user nhn ca email v n gi mail cho MDA trn host2.uiuc.edu
    • MDA trn host2.uiuc.edu s gi mail n mail box ca user nhn
    • Khi user nhn dng mt MUA no log vo mail box ca mnh check mail anh ta s c c mail ca mnh.
  • 7. Mime(Multipurpose Internet Mail Extension)
    • Chun MIME c nh ngha cho php truyn d liu ko phi l ASCII qua th in t, n cho php d liu bt k c m ha trong dng ASCII ri c truyn trong thng ip th in t chun.
    • chp nhn c kiu d liu bt k cng nh cch th hin, mi thng ip MIME bao gm thng tin thng bo cho ni nhn bit kiu d liu v cch m ha chng.
    • MIME s dng m ha Base64 chuyn cc file phc tp sang ASCII
  • 8. MIME c th c m t trong nm phn:
    • Cc giao thc cho cc i tng khc ngoi mail vn bn ASCII.
    • C cu tng th ca cc phng tin truyn thng MIME nhp h thng, c mt nh ngha ban u thit lp cc loi phng tin truyn thng.
    • Mt giao thc cho cc bng m ASCII vn bn trong cc phm vi tiu ca th thng ip.
    • Nhiu th tc ng k IANA MIME lin quan n c s.
    • MIME ph hp tiu chun .
  • 9. Cc tiu chun ca MIME c thit k vi th t u tin chung sau y
    • Kh nng tng thch vi cc tiu chun hin c, chng hn nh RFC 2822
    • Mt u tin k tip l s dng mnh m trn thc t hin ti .
    • Mt u tin xem xt khi thit k MIME l c kh nng m rng d dng.
  • 10. 15.3.1 Hot ng ca MIME
    • phi bao gm mt trng header vi C php:
    • Keyword: Value
  • 11. MIME-Version
    • V d: MIME-Version: 1.0
    Cc trng Content-Type C php: Content-Type: type/subtype; tham s = gi tr; tham s = gi tr Tiu chun Content-Type Vn bn Multipart nh Video Audio Application
  • 12. Vn bn Cho bit du cch trong fixed hoc flowed vn bn phi c bo qun hoc xa. DelSp Cc d liu bao gm fixed c nh hoc flowed text, ch ra chnh xc bn cht ca vn bn Format x nm trong khong t1 n 9 ca tiu chun ISO-8859. Vn bn ny bao gm cc k t ISO trong khong t 0 n 255 Iso-8859-x Cc ch vn bn bao gm cc k t ASCII trong khong 0-127 Us-ascii
  • 13. Multipart
    • Phn ni dung tin nhn c th cha nhiu kiu i tng d liu ring. Trong mi trng hp, phn ni dung c chia thnh cc phn ring bit, c gi phn l tm lc . Ni dung ca nhng phn tm lc c nh ngha vi mt tham s trong content-type , v d:
    • Content-Type: multipart/mixed; boundary="1995021309105517
    • C 4 gi tr sau:
    l mt bin th trn multipart/mixed Digest tng cc phin bn so vi bn gc, v h thng email ca ngi nhn s hin th phin bn tt nht Alternative Ch khc vi mixed ch khng c th t gn cho cc phn. V vy, chng trnh c th nhn c mail hin th tt c chng ngang hng. Parallel Chng phi c trnh by cho ngi nhn theo th t m chng xut hin trong email. Mixed
  • 14.
    • Ni dung cha d liu nh i hi phi c mt mn hnh ha hoc mt s thit b khc hin th n.
    • Cc hnh nh c nh dng JPEG, GIF.
    nh Video
    • Ni dung cha d liu hnh nh chuyn ng (c th vi m thanh ng b) i hi phi c thit b thng minh hoc my trm a phng tin hin th n.
    • Video c nh dng MPEG.
    Audio
    • Ni dung cha d liu m thanh i hi phi c loa v card m thanh (hoc phn cng tng t) hin th n.
    • basic: Mt nh dng mu s ph bin thp nht ca bt k tiu chun m ha m thanh. C th, l knh ISDN mu-law 8-bit m ho vi t l mu ca 8 kHz.
  • 15. Application
    • Dng cho cc d liu c x l bi mt chng trnh ng dng trc khi c trnh by cho ngi s dng
    • C 2 dng:
      • PostScript
      • Octet-stream
  • 16. 15.3.2 Cc trng Content-Transfer-Encoding
    • Content-Transfer-Encoding: field
    • field nh ngha m ha c s dng
    • Nm dng m ha l:
    m ha 7-bit 8-bit Binary Quoted-in Base64
  • 17. 15.4 Post Office Protocol (POP)
    • Post Office Protocol phin bn l mt giao thc tng ng dng, dng ly th in t t server mail, thng qua kt ni TCP/IP
    • N hot ng kt hp vi giao thc SMTP cung cp dch v chuyn th n gin
  • 18. Cc phin bn ca POP
    • POP1
    • POP2
    • POP3
  • 19. Phin bn POP3
    • Khi POP3 ra i, ngay lp tc thay th hon ton cc phin bn c. V vy, ngy nay, nhc n POP th thng l m ch POP3.
    • Thit k ca POP3 h tr chc nng cho ngi dng c kt ni internet khng thng trc (nh kt ni dial-up),
  • 20. Cc lnh ca pop3
    • USER :Ch r username
    • PASS :Ch r password
    • STAT: Yu cu trng thi ca mailbox (s lng message, kch thc ca cc message)
    • LIST: Lit k cc message
    • DELE: Xa mt message c th
    • QUIT :Chp nhn cc thay i v ct kt ni.
  • 21. S khc bit gia POP v SMTP
    • POP3 l giao thc dng nhn mail t mt mail server
    • SMTP l giao thc dng gi mail ti mt mail server
  • 22. Internet Message Access Protocol (IMAP)
    • IMAP l th h mi ca giao thc POP .Ni mt cch n gin, IMAP t s kim sot email trn mail server trong khi nhim v ca POP l ti ton b thng ip email v client server yu cu.
    • IMAP cung cp truy cp email theo ba ch khc nhau: offline (ngoi tuyn), online (trc tuyn) v disconnected (ngt kt ni).
  • 23. Truy cp ch offline
    • Ging nh POP, cc thng ip email c truyn n my client server, xa khi mail server v mi lin kt b ngt. Sau ngi dng c, tr li, lm cc vic khc ch ngoi tuyn, v nu mun gi th mi i h phi kt ni li.
  • 24. Truy cp ch online
    • L ch IMAP truy cp m ngi dng c v lm vic vi thng ip email trong khi vn ang gi kt ni vi mail server (kt ni m). Cc thng ip ny vn nm mail server cho n khi no ngi dng quyt nh xa n i. Chng u c gn nhn cho bit loi "c" hay "tr li".
  • 25. Truy cp ch disconnected
    • IMAP cho php ngi dng lu tm thng ip client server v lm vic vi chng, sau cp nht tr li vo mail server ln kt ni k tip. Ch ny hu ch cho nhng ai dng laptop hay truy cp mng bng in thoi,
  • 26. Xin chn thnh cm n !