Does effective Simultaneous-Use requires radutmp or database to work OK ?

[Olivier]

Hello,

In a WPA2 Enterprise wireless environment, I'm trying to control the
number of simultaneous connections a user can have.
My setup includes Freeradius 3.0.21 from Debian Bullseye's repo.

I've seen this Simultaneous-Use setting in documentation.

When testing it, I thought I first needed to have radutmp working OK.
Unfortunately, my WiFi AP (Unifi AP) do not send NAS-Port AVP in
Account-Requests.
This seems to prevent radutmp (and checkrad) to work OK.

At the same time, I can see meaningful and accurate data in my
/var/log/freeradius/racacct directory.

So my my question are:

1. When both NAS-IP-Address and NAS-Port are present in
Accounting-Requests, is checkrad or radwho using them to send some
request to the NAS ?

2. Is radutmp required for Simultaneous-Use enabling ?

3. If radutmp is not required, is an SQL database required for
Simultaneous-Use ?

Best regards