?12? ?????E-mail??

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?12? ?????E-mail??

• ??? ??????
• ???????????

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???????????????????????????????????(?SMTP
?POP3?IMAP?)?

• ????UA(User Agent)???????????????????????????????
  ???????????
• ?????????????????,?????????????????,?????????????
  ?????
• ????????Internet?????????????????????????????????
  ????SMTP?POP3?IMAP????

3
??????????

• ??????_at_?????????
• ???????????
• (1)????????????????????????SMTP???????????????
• (2)????????????????????,?????

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(3)SMTP????/????????????????????SMTP????,?????????
??????,??????????????SMTP???????TCP??????

• (4)?TCP?????,SMTP??????????SMTP???????????????????
  ??,?SMTP?????????????SMTP????????????????,SMTP????
  ???TCP???

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(5)?????????????SMTP??????????,??????????????,????
???????????

• (6)?????????,??POP3(?IMAP)????????????????????????
  ??

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??? ???????

• ??SMTP??
• SMTP(Single Mail Transfer
  Protocol,????????),???????????????????????????,???
  ?TCP???25?
• ???SMTP????????????SMTP????SMTP??????????????
  ?,????SMTP?????????,??????SMTP??????????

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SMTP?????

• ????
• ???????????????????SMTP????????????????????????,
  ???SMTP?25????????SMTP?????TCP???
• 2. ????
• ???????MAIL?????MAIL????????????
• ?????????RCPT??,?????????????????????

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?????DATA??,?????????????

• 3. ????
• ???????,SMTP?????QUIT???SMTP?????????250
  OK?SMTP?????TCP?????,?SMTP??????,?????????????

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??POP3??

• POP3(Post Office Protocol Version
  3,????,??3),???????????????????????????????,????TC
  P???110?
• ???POP3????????????POP3????POP3???????????????
  ????POP3?????????,??????POP3????????????
• POP?????/?????????

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??IMAP??

• IMAP(Internet Message Access
  Protocol,Internet??????),?????????????????????????
  ????,????TCP???143?
• IMAP???????/??????? ?
• IMAP????????

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IMAP?POP?????

• ??POP,????????????????????????ISP?????,???????
  ???????????????????????????????????,??????????????
  ??????
• ???IMAP?,?????????????ISP???????IMAP??????????
  ?????IMAP????,???ISP????????IMAP???????TCP????????
  ?PC???????ISP?????????,????????? ?

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??? ???????
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??POP??
14
????
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Internet????(IIS)???
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??? ??SMTP???

• ??SMTP?????

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????SMTP?????

• 1. ?????

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2. ?????
19
?????
????
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3.?????
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4.?????
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???????
????
23
5.LDAP?????
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??? ??POP3???

• ??POP3?????

25
?????
26
????????
27
?????????
28
???????
29
??? ??????

• ??Outlook Express??SMTP?????

30
???????
31
??????
32
??????
33
?????????IP??
34
?????
35
???????
36
?????
37
??????
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??SMTP????????