POP3

Post Office Protocol - Version 3

POP

Short for Post Office Protocol, a protocol used to retrieve e-mail from a mail server. Most e-mail applications (sometimes called an e-mail client) use the POP protocol, although some can use the newer IMAP (Internet Message Access Protocol). There are two versions of POP. The first, called POP2, became a standard in the mid-80's and requires SMTP to send messages. The newer version, POP3, can be used with or without SMTP.

POP3 is the latest Post Office Protocol 3, this is a service that stores and serves emails for various client machines that are not connected to the Internet 24 hours a day. Emails are held in POP3 until you log in.

POP3-mail-clients: http://directory.google.com/Top/Computers/Software/Internet/Clients/Mail/?tc=1/

Using Telnet with a POP3 Mail Server: http://pages.prodigy.net/michael_santovec/pop3telnet.htm

RFC: http://www.ietf.org/rfc/rfc1939.txt

USER userid This must be the first command after the connect. Supply your e-mail userid (not the full e-mail address). Example: USER john.smith

PASS password This must be the next command after USER. Supply your e-mail password. The password may be case sensitive.

The following commands may be used as needed:

STAT The response to this is: +OK #msgs #bytes Where #msgs is the number of messages in the mail box and #bytes is the total bytes used by all messages. Sample response: +OK 3 345910

LIST The response to this lists a line for each message with its number and size in bytes, ending with a period on a line by itself. Sample response: +OK 3 messages 1 1205 2 305 3 344400.

RETR msg# This sends message number msg# to you (displays on the Telnet screen). You probably don't want to do this in Telnet (unless you have turned on Telnet logging). Example: RETR 2

TOP msg# #lines This is an optional POP3 command. Not all POP3 servers support it. It lists the header for msg# and the first #lines of the message text. For example, TOP 1 0 would list just the headers for message 1, where as TOP 1 5 would list the headers and first 5 lines of the message text.

DELE msg# This marks message number msg# for deletion from the server. This is the way to get rid a problem causing message. It is not actually deleted until the QUIT command is issued. If you lose the connection to the mail server before issuing the QUIT command, the server should not delete any messages. Example: DELE 3

RSET This resets (unmarks) any messages previously marked for deletion in this session so that the QUIT command will not delete them.

QUIT This deletes any messages marked for deletion, and then logs you off of the mail server. This is the last command to use. This does not disconnect you from the ISP, just the mailbox.