HelpSpot

HelpSpot is a web-based help desk software for managing all customer support needs - email, self-service knowledge base, full reporting and so much more. Unlike other systems, HelpSpot is infinitely flexible - host it yourself or have it hosted, use your own email systems, authenticate with active directory, LDAP or via custom logic. Best of all, with HelpSpot, there are no limits - unlimited tickets, customers, knowledge base articles, API calls, and custom fields.