In yet another update to the Client Portal feature, now you can limit a contact to see only tickets to which he or she is assigned.
By default, a contact using Client Portal will see all tickets or tasks assigned to any contact in his or her whole company. This is useful for project teams where multiple contacts might be concerned about a single project.
But for helpdesk teams, contacts using Client Portal should only be concerned about their own personal tickets. Now you can restrict contacts to only see tickets they are the contact for.
Here's how you configure it right now: