O'Reilly logo

Ubuntu Unleashed 2014 Edition: Covering 13.10 and 14.04,Ninth Edition by Paul Hudson, Andrew Hudson, Matthew Helmke

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

How Email Is Sent and Received

Email is transmitted as plain text across networks around the world using the Simple Mail Transfer Protocol (SMTP). As the name implies, the protocol itself is fairly basic, and it has been extended to add further authentication and error reporting/messaging to satisfy the growing demands of modern email. Mail transfer agents (MTAs) work in the background transferring email from server to server, allowing emails to be sent all over the world. You might have come across such MTA software such as Sendmail, Postfix, Fetchmail, Exim, or Qmail.

SMTP allows each computer that the email passes through to forward it in the right direction to the final destination. When you consider the millions of email servers across ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required