You do not need to install Webmin to set up an SMTP server; however, unless you really enjoy the command line Webmin will make administration of your SMPT server much easier. I prefer a GUI, so this guide will show you how to install and configure Webmin on Ubuntu Server.  Also the rest of the instructions will be based on a Webmin installation.

1. We will download webmin from http:www.webmin.com .
   Type:
   wget http://www.webmin.com/download/deb/webmin-current.deb
   press Enter.
   
   You should see a lot of text then a percent as the file downloads.
2. Now we will extract the downloaded webmin package, install it, and make sure everything is up to date.
   Note:  Accept defaults and enter Y for yes when asked.Type:
   sudo dpkg –i webmin-current.deb
   press Enter.
   Type:
   sudo apt-get –f install
   press Enter.
   Type:
   sudo apt-get update
   press Enter.
   Type:
   sudo apt-get upgrade
   press Enter.
   Type:
   sudo reboot
   press Enter.
3. You should now be able to access your server via webmin.  Go to another computer, launch a browser and go to:
   https://[serverIP]:10000
   Note: Replace serverIP with the IP of your Ubuntu Server you created in the sectionChange Ubuntu Server from DHCP to a Static IP address step 3 of How to set up a 

http://www.itshouldwork.org/2011/04/installwebmin/