This is a simple step-by-step tutorial to install and configure exim to route all e-mails send though a local SMTP server to one local user, regardless of the e-mail address or domain. I found this set-up very usefull when testing applications that send e-mail messages and you do not want to generate multiple HotMail accounts for testing or in case I'm wanted to do some testing and development when I'm offline.

Install exim

Start with installing exim.
user@devmachine:~$ sudo apt-get install exim4