We are currently using this SMTP server by Argosoft for sending emails from various web applications running on different servers throughout our network. This thing runs great but I would like to ditch the windows based app and set up a VM running Ubuntu 10.04 as a replacement. All I need is a simple SMTP server to handle sending emails, It does not need to receive but it does need to send mail from other servers on the network. I've googled around a bit but everything seems to be more complex than what I need. Can anyone recommend a good "How-To" article on setting up a SMTP server such as this? Thanks in advance for any help you can offer.
Have a look at postfix. Its already available on Ubuntu 10.04.
A simple HOWTO on getting postfix up and running. https://help.ubuntu.com/community/PostfixBasicSetupHowto
You dont need to bother with the IMAP and POP3 part since your server is not going to receive emails
I did something similar to this on ubuntu using dovecot and exim4. We switched to Google Apps and I needed an SMTP relay for our dadamail server and hardware devices that don't support authenticated SMTP. We got up and running in a few hours using the following pages as a reference. If you don't need mailboxes to live on the server, just install exim. Setup is all menu driven during the installation and it didn't cause me any headaches to get up and running!