For testing purpose, for instance with notifications, you often need to setup an SMTP server. There is an easy way to setup a local smtp server by using this project : http://nilhcem.github.io/FakeSMTP/. It binds a dummy SMTP server that listens on whichever port you want (that also mean that those mails won't be really sent) and on which you can setup Nuxeo to send outgoing mails : when the server sends a mail, it shows up into the list of received EMails.
To get this up and running, you only need to adjust your $NUXEO_HOME/bin/nuxeo.conf file to reflect this setup.
$NUXEO_HOME/bin/nuxeo.conf
...
# Mail settings (for notifications)
#nuxeo.notification.eMailSubjectPrefix="[Nuxeo]"
mail.transport.host=localhost
mail.transport.port=25000 # Adjust with FakeSMTP configuration. Avoid port 25 that is generally used by other applications.
#mail.transport.auth=
#mail.transport.user=
#mail.transport.password=
#mail.from=
...
To start the software, just launch the command :
java -jar fakeSMTP.jar
For Windows users, you can check this software that seems to do the same job : http://smtp4dev.codeplex.com/