P.O.P.

1
P.O.P.

• A presentation brought to you by
• Thomas

2
Topics

• Introduction
• General Information
• Area of use
• Functionality
• The alternative way
• POP3 vs. IMAP
• Conclusion

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What is POP

• Post Office Protocol
• Actual Version is POP3
• Responsible for recieving emails from a
  mailserver
• Most widely implemented protocol for retrieval of
  Internet Mail

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General information

• Standard Port for POP3 is 110
• Session Layer
• Platform independent
• RFC 1939
• Email service provider need to install a POP3
  server for offering POP.
• POP3 transferred emails are secured by SSL or TLS

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Area of use

• Supported by most mail client applications
• TCP/IP Networks
• Free internet mail services
• - ...but mostly IMAP is provided on a higher
  service level

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How does it work

• XXX_at_YYY.ZZ
• XXX indicates the user who is
• registered at the webdomain YYY.ZZ
• -The user logs in to the webdomain
• via email client. Password and account
• will be checked.
• -If validation is correct, POP3 of the
• client requests download of new mails.

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How does it work II

• POPserver of mail provider accepts the request,
  if there are no problems.
• Download will be initialized by mail client
  application.
• All mails could be deleted from the mailbox on
  mailserver. (optional)
• After download connection will be closed again.

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For the one without mail client...

• Via telnet direct connection to mailbox using POP
  (PlainTextLogin).
• Commands
• USER Login
• LIST shows the content of mailbox
• RETR downloads selected mail
• DELE deletes selected mail
• QUIT Closes connection from hostside

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• telnet pop.gmx.net 110
• Trying 213.165.65.60...
• Connected to pop.gmx.net.
• Escape character is C'.
• OK GMX POP3 StreamProxy ready lt31592.1053333688_at_m
  p006-rz3gt
• USER cartman666_at_gmx.de
• OK May I have your password, please?
• ltCENSOREDgt
• OK mailbox has 3 messages (5985 octets)

Login procedure
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• LIST
• OK mailbox has 3 messages (5985 octets)
• 1 1845
• 2 2616
• 3 1524
• .
• RETR 1
• OK message follows
• Return-Path ltJohn.Doe_at_Foobar.comgt
• X-Flags 0000
• Delivered-To GMX delivery to cartman666_at_gmx.de
• ... (MAIL)

checkmail procedure
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• ...(MAIL END)
• DELE 1
• OK message deleted
• QUIT
• OK bye
• Connection closed by foreign host.

Delete/Logout procedure
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POP3 vs. IMAP

• IMAP is suitable for online access to a mailbox
  service, where messages are stored and filed on a
  permanent or semi-permanent basis on the server.
• POP3 is suitable for a mailbox service, where
  messages are only stored for a temporary period
  on the server.
• POP3 is less complex.
• Generally IMAP is used in companies, POP is used
  by private email users.

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Conclusion

• Everyone who plans to implement an email system
  should think about using IMAP or POP3, depending
  on his needs.
• Easy and fast working.
• For private use adequate, but companies with
  bigger mailing systems should use IMAP.

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Thank you for your attention...
...any questions?