#Postfix install
sudo apt-get install postfix libsasl2-modules mailutils
#select intener site and put the email domain


#create in /etc/postfix/sasl_passwd
nano /etc/postfix/sasl_passwd
## and add
[smtp.gmail.com]:587 username@gmail.com:password

#charge the pass to db
sudo postmap /etc/postfix/sasl_passwd

#only root can see files with passwords (use one of the 2 options)
sudo chown root:root /etc/postfix/sasl/sasl_passwd /etc/postfix/sasl/sasl_passwd.db
sudo chmod 600 /etc/postfix/sasl_passwd /etc/postfix/sasl_passwd.db

#config mainfile in /etc/postfix/main.cf
nano /etc/postfix/main.cf
#change
relayhost = [smtp.gmail.com]:587
#and add to the end
###########################
# enable SASL authentication
smtp_sasl_auth_enable = yes
# disallow methods that allow anonymous authentication.
smtp_sasl_security_options = noanonymous
# where to find sasl_passwd
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
# Enable STARTTLS encryption
smtp_use_tls = yes
# where to find CA certificates
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
############################

#restart with systemctl
sudo systemctl restart postfix

#do a test
sendmail recipient@gmail.com
FROM: youremail@gmail.coms
SUBJECT: Hello from your server!
This is a test email sent from your server by Postfix.
.

#check in the logs and the email
nano /var/log/mail.log (or mail.err)

#if something is wrong, can reconfig postfix with this
sudo dpkg-reconfigure postfix

#also can check allias
nano /etc/aliases


####flush mails###########

#View queued
postqueue -p

#Flush queued mail
postqueue -f

#Purge 1 msg
postsuper -d [message id]

#Purge all
sudo postsuper -d ALL