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Some network application protocol examples

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• Getting a webpage from www.mathcs.emory.edu
  • How a web client (e.g., Firefox) get a webpage from a webserver:

    >> telnet www.mathcs.emory.edu 80 Trying 170.140.150.5... Connected to webprod2.mathcs.emory.edu. Escape character is '^]'. GET http://www.mathcs.emory.edu HTTP/1.0

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• Send an email as God@heaven.com

  • How a mail client (e.g., Thunderbird) sends a email:

    cheung@compute(1003)> telnet cssun.mathcs.emory.edu 25 Trying 170.140.150.1... Connected to cssun. Escape character is '^]'. 220 cssun.mathcs.emory.edu ESMTP Sendmail 8.13.8+Sun/8.13.8; Mon, 18 Jan 2010 11:30:15 -0500 (EST) helo compute.mathcs.emory.edu 250 cssun.mathcs.emory.edu Hello compute [170.140.150.8], pleased to meet you mail from:God@heaven.com 250 2.1.0 God@heaven.com... Sender ok rcpt to:cheung 250 2.1.5 cheung... Recipient ok data 354 Enter mail, end with "." on a line by itself subject:Your behavior You have been really bad... . 250 2.0.0 o0IGUF3F029127 Message accepted for delivery quit 221 2.0.0 cssun.mathcs.emory.edu closing connection Connection to cssun closed by foreign host. Thou hast new mail

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