I am searchig for a way for avoiding more than one user to register softphones with the same username/password.
I’m using freepbx with pjsip extensions. My problem is sometimes softphones have wrong or copied configs and repeats the number and both of them can make calls and people thinks they are ok.
I need to either reject the second registration or kill and replace the current connection.
I have max contacts = 1 but it only affects receiving calls (only one of the registered terminals rings). What I need is the ohter terminals not working at all, not receiving nor initiating calls so the users know there is a problem.
Is it possible? I’m using freepbx but if it’s needed I can patch manually the configs.
The problem is how do you know who the correct user is if you give them all the same credentials ?
How do you differentiate the new incoming registrations from normal IP address changes ?
What max_contacts=1 is doing is bumping off the previous phone every time a new phone registers.
Instead you might want to set max_contacts=99 and then just let them register and periodically call the number to get all the duplicated soft phones ringing. Keep doing that, and users may start to complain about missed calls , effectively de-anonymizing themselves and opening up the opportunity for increased user training with new login credentials (and a new HOWTO from you that does not include any sample/default credentials!)
EDIT: Thread was closed - edit seems only option to make an update - But, in case it was not clear, the max_contacts change is not going to affect outbound, only inbound to those phones. So you might try changing the user/pass in your FreePBX configs from the shared user/pass that all your users copy/pasta’d - that breaks them all, yes, just be ready for the support tickets (and maybe notify them ahead of time that as of X date in the future they may need to change their credentials.)
Kicking the previous registration is OK for me. Any “abnormal” behaivor will do. What I need one of all the users that are sharing the same extensio can’t make new calls. Then they will ask for a solution and I will fix the misconfiguration.
But I tried max_contacts=1 and they can make calls anyway.
and then just let them register and periodically call the number to get all the duplicated soft phones ringing. Keep doing that, and users may start to complain about missed calls 
, effectively de-anonymizing themselves and opening up the opportunity for increased user training with new login credentials (and a new HOWTO from you that does not include any sample/default credentials!)