OTRS Help Desk is an open source application (with Enterprise support) that has a lot of useful features: ITSM, Surveys, Time Accounting and System monitoring.
I use it on my company as a Service Desk for Security purposes (and more).
As you can read from our Success Story one of the feature we currently appreciate is the ability to track all the email exchanges into tickets simply putting ticket number in email Subject end CCing the proper configured email address. This allow us to interact with external parties without the need for other people to access our OTRS istance. Continue reading “Configure OTRS to process multiple Tickets in email Subject”