Скачать или смотреть How to install Postfix in Ubuntu

Installing Postfix:
sudo apt update && apt upgrade -y
sudo apt install postfix -y

Changing the Postfix Configuration:
sudo postconf -e 'home_mailbox= Maildir/'
sudo postconf -e 'virtual_alias_maps= hash:/etc/postfix/virtual'
sudo nano /etc/postfix/virtual
paste
[email protected] quick
[email protected] quick

sudo postmap /etc/postfix/virtual
sudo systemctl restart postfix
sudo ufw allow Postfix

Installing the Mail Client:
echo 'export MAIL=~/Maildir' | sudo tee -a /etc/bash.bashrc | sudo tee -a /etc/profile.d/mail.sh
source /etc/profile.d/mail.sh
sudo apt install s-nail
sudo nano /etc/s-nail.rc
paste
set emptystart
set folder=Maildir
set record=+sent

echo 'init' | s-nail -s 'init' -Snorecord quick


ls -R ~/Maildir

Testing the Client:
s-nail
nano ~/test_message

type test message
Hello,

This is a test. Please confirm receipt!

cat ~/test_message | s-nail -s 'Test email subject line' -r [email protected] [email protected]

s-nail
file +sent

example.com