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QUALCOMM Incorporated
Mail Transport
Introduction
Eudora uses Simple Mail Transfer Protocol (SMTP) to transfer your outgoing mail to you r
SMTP server machine, which in turn uses SMTP to send your mail to th e world at large.
Mail from the world at large arrives on your incoming Post Office Protoco l (POP) or
Internet Message Access Protocol (IMAP) mail server, where it waits for Eudora to pick it
up with either POP version 3 or IMAP version 4. The mail Eudora sends a nd receives is
constructed in accordance with RFC 822 and RFC 2045 (MIME).

Eudora mail transport overview, POP (similar for IMAP)

Outgoing Mail

When you send an email message to someone, Eudora uses SMTP to send the mail to
your local SMTP server computer. That computer then sends the mail to your addressee’s
computer, also (usually) by means of the SMTP protocol.
Why doesn’t Eudora talk directly to your addressee’s computer? For one thing, it would
take a lot longer for your mail to leave your computer because your computer would hav e
to call up each addressee’s computer and deliver your mail. For another, some computers
are “hard to find”; it’s much better to let another computer “hunt” for your addressee than
to make your computer do it. Finally, sometimes your addressee’s computer won’t be
available when you want to send mail. The SMTP server handles this by hol ding your mail
until the other computer is ready to accept it, eliminating the inco nvenience of having
unsent messages hanging around on your computer.
Your Macintosh POP/SMTP
Server
The World at Large
POP
Check Mail
SMTP
Send Queued Messages
SMTP
Your PC
Check Mail
Send Queued Messages