To create a Postfix relay Server ensure you have the appropriate Linux distribution installed on a Virtual Server.

Type the following command to install postfix:

sudo apt install postfix

You need to select mail server type:

Select Internet Site:

Type fully qualified name of your domain such as flakie.org

Edit /etc/postfix/main.cf, enter:

sudo nano /etc/postfix/main.cf

Set myhostname to FQDN as configured earlier

myhostname = bash.cyberciti.biz

Save and close the file.