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linux:smtp-tutorial [2019/01/21 11:28] (current)
seanburns created
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 +<​markdown>​
 +# Email Basics and SMTP Tutorial
 +## Date: Tue 27 Nov 2018 
  
 +## POP and IMAP: Receiving mail
 +
 +- POP: Ports 110 and 995
 +
 +POP, the Post Office Protocol: Generally, email clients that use POP will
 +download email to a local system (e.g. your laptop) and then delete the emails
 +from the remote server.
 +
 +- IMAP: Ports 143 and 993
 +
 +IMAP, the Internet Message Access Protocol: More flexible than POP. The default
 +is to leave email messages on the remote server until the user explicitly
 +deletes them. IMAP was designed to enable access to email from multiple email
 +clients (e.g., email client on laptop, on desktop, and on phone,
 +simultaneously).
 +
 +## SMTP: Sending mail
 +
 +- SMTP for sending mail: Ports 25, 465, and 587
 +
 +SMTP, the Simple Mail Transfer Protocol: to route and deliver messages.
 +
 +## Key terms:
 +
 +- Mail Transfer Agents (MTA) -- e.g., Postfix
 +- Mail Delivery Agent (MDA) -- retrieve email from remote server
 +- Mail User Agents (MUA) -- e.g., email client
 +
 +## Install Postfix, an SMTP server
 +
 +Check for and install any updates, and then install Postfix and mailx:
 +
 +```
 +sudo dnf check-update
 +sudo dnf -y upgrade
 +sudo systemctl reboot ​          # new kernel update; reboot required
 +sudo dnf -y install postfix mailx
 +```
 +
 +Enable Postfix on startup using systemd, and then start Postfix:
 +
 +```
 +sudo systemctl enable postfix.service
 +sudo systemctl start postfix.service
 +sudo systemctl status postfix.service ​  # check its status
 +```
 +
 +Test the SMTP connection:
 +
 +```
 +telnet localhost 25
 +ehlo localhost
 +mail from: sean@localhost
 +rcpt to: sean.burns@uky.edu
 +data
 +Subject: this is my first email
 +
 +Hi,
 +
 +What's up? Let me know!
 +
 +- root
 +.
 +quit
 +```
 +
 +Then use ``mailx`` on sweb or sised. E.g.:
 +
 +```
 +ssh user@sised
 +mail -s "hello there" other-user
 +```
 +</​markdown>​
linux/smtp-tutorial.txt ยท Last modified: 2019/01/21 11:28 by seanburns