When building integrations with JBoss ESB you naturally need to interact with other systems via notification gateways other than messaging queues. It could be that you need to enrich data from a WS-SOAP service or just put data into a file in a specific directory. These addresses and location often need to be different depending on which environment you are running in.
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.
Start with installing exim.
user@devmachine:~$ sudo apt-get install exim4