1. Ensure your system is up-to-date:
apt-get update
apt-get upgrade
2. Install the libsasl2-modules
apt-get install libsasl2-modules
3. Installing Postfix
apt-get install postfix
General type of mail configuration is Internet Site and System mail name is fully qualified domain like mail.example.com
4. Update file /etc/postfix/main.cf
myhostname = mail.example.com
5. Create a like name sasl_password
nano /etc/postfix/sasl_passwd
and update as follwoing
[smtp.office.com] username:password
6. Create a Hash database file for Postfix using
postmap /etc/postfix/sasl_passwd
7. Run the following command to change file’s permissions
chown root:root /etc/postfix/sasl_passwd /etc/postfix/sasl_passwd.db
chmod 0600 /etc/postfix/sasl_passwd /etc/postfix/sasl_passwd.db
8. Open /etc/postfix/main.cf and update as follwoing
nano /etc/postfix/main.cf
# specify SMTP relay host
relayhost = [smtp.office.com]:587
# 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
8. service postfix restart
