Forcing users to change password on first login

[senor_paul]

Hi folks I've got a quick question.
I am setting up a Captive Portal through pfsense using RADIUS2 user authentication. I have the system up and tested and everything is working well. The system is going to be deployed into a corporate environment with approx 200 users. I have created all the user accounts with their passwords set to 'password'. The plan is that when a user logs on for the first time, they are forced to change their password. Is this at all possible? I am not fixed to the RADIUS authentication, if it helps solve the problem I could switch back to the pfsense user authentication.

I have searched through this forum and the web and am struggling to find a solution.

Cheers!