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( Post Office Protocol - Version 3 )

POP3. ( Post Office Protocol - Version 3 ). RFC 1939. 報告學生 : 駱正哲. POP3. smtp server. smtp port. POP3 Server. mail drop. User Agent. TCP port 110. POP3. message format. 40 characters. command arguments CRLF case-insensitive. (status indicator) responses CRLF. +OK -ERR.

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( Post Office Protocol - Version 3 )

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  1. POP3 ( Post Office Protocol - Version 3 ) RFC 1939 報告學生 : 駱正哲

  2. POP3 smtp server smtp port POP3 Server mail drop User Agent TCP port 110

  3. POP3 message format 40 characters command argumentsCRLF case-insensitive (status indicator) responsesCRLF +OK -ERR 512 characters (status indicator) responsesCRLF responsesCRLF responsesCRLF responsesCRLF.CRLF

  4. POP3 greeting USER / PASS AUTHORIZATION Three stages APOP POP3 AUTH QUIT LIST,RETR,DELE …… TRANSACTION QUIT UPDATE

  5. POP3 AUTHORIZATION STAGE USER / PASS USER name response : +OK Password required for name. PASS string response : +OK name has n messages (m octets). space acceptable Plaintext dangerous

  6. POP3 AUTHORIZATION STAGE APOP 1. A timestamp in greeting Timestamp ex. <process-ID.clock@hostname> 2. APOP user digest 16 octets Hexadecimal ( and lower-case ASCII)

  7. POP3 AUTHORIZATION STAGE MD5 timestamp shared secret digest

  8. POP3 AUTHORIZATION STAGE POP3 AUTH +OK maildrop locked and ready -ERR authentication exchange failed AUTH mechanism : server challenge : +(BASE64 encoded string) client answer : (BASE64 encoded string) client cancel : *

  9. POP3 AUTHORIZATION STAGE Exclusive-access lock on the maildrop Mailbox Mailbox new mail new mail Mailbox Pop3 client

  10. POP3 TRANSACTION STAGE STAT : issue a drop listing for that maildrop number of messages response : +OK nn mm total size in octet (decimal) STAT +OK 10 7817

  11. POP3 TRANSACTION STAGE LIST (msg) : List messages in the mailfrop or issue a scan listing for that message LIST 9 +OK 9 661 LIST +OK 10 messages (7817 octets) 1 528 2 852 3 852 4 852 5 852 6 852 7 852 8 852 9 661 10 664 .

  12. POP3 TRANSACTION STAGE RETR msg : +OK (message body) -ERR no such message DELE msg : +OK message deleted -ERR no such message NOOP : +OK

  13. POP3 TRANSACTION STAGE UIDL (msg) : +OK unique-id listing -ERR no such message 1 ～ 70 characters Between : 0x21 ～ 0x7E HASH message unique - id

  14. POP3 TRANSACTION STAGE UIDL +OK uidl command accepted. 1 e73f7d065d8ca4c4388ee3123c2b855a 2 1493e2eff10ccce447c30c3a3f78b610 3 a9df87f9ca8ccbf72cb095c2ba643027 4 ed16b3f3f00b53d0a7553eec96082efc 5 0a537b201c8859977a133ee771f5f45b 6 8451993202d8cc7da7d713548b5ea174 7 32653368f747914f6e48c98692c38bf9 8 fab3686e92be670ebe5e2514563cc44b 9 076ac86d0efeea6bca94240b4282f119 10 5b3beb2d4c42f3563c19135b0ec0ff29 .

  15. POP3 UPDATE STAGE Remove message marked deleted Close TCP connection

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