Restrict account

I find that several users can register the asterisk system based on a same iax account at same time and can make call simultaneously.
How can i restrict an account only allow one call at a same time?

"call-limit = number : Number of simultaneous calls through this user/peer."
it is from sip.conf … g+sip.conf
but try it in iax.conf

call-limit take no effect in iax.conf. instead of restricting simultaneous calls, can i restrict only one user iax user can register at the same time based on the same account.

Anyone any experience about it? Thank!!!

does ‘several users’ have the same IP adress ?
host=ip can be set for iax, it should set the range of simultaneus
registration to one ip.

I will restrict simultaneous register base on account but not based on ip.
I mean one iax user account will only allow one user register at the same time.