Web-based task tracker?

Need a task tracker and remote access. Office server for some reason to stick out can not, therefore, need tracker on the Internet.


What I want:


free

— tickets with statuses

— maintenance of versions/releases

— separation of user rights (for projects, actions)

— timetracking

— ability to organize subtasks, or at least linking tickets

— reports status as a big plus — diagrammi (Gantt or burndown)


It is clear that all requirements are likely incompatible in the free trackers, but I'm happy to hear suggestions. If you can, briefly describe what the proposed tracker is present. Thank you!