Reload Freeradius clients without restart the service

I looked at the URL you provided and I found that an interesting way of doing it. I would seriously consider the fact that the example is possibly outdated before relying on it.

On our FreeRadius implementation we get around the accounting updates problem by setting a timeout in our Radius database. We do this by having a Attribute "Session-Timeout" op "=" and Value "86400" in the radgroupreply table.

This has the effect of "timing out" the user every 24 hours. Most PPPoE clients (including ADSL and MikroTik routers) are programmed to reconnect strait away. This is normally a split second operation on a MikroTik client router and in theory not that disruptive. My tests have however shown that it can in fact break certain TCP/IP operations, e.g. downloads.

However, the method we use seems very reliable and a good failover method if your interim updates fail or your disconnect method breaks.

I haven't used a database backend before, but using the users file the rule would look something like this:

myuser  Cleartext-Password := "mypass", NAS-IP-Address == "192.168.2.1"

Based on that, I think you need two entries in the radcheck table:

usernane='myuser', attribute='Password', op=':=', value='mypass'
username='myuser', attribute='NAS-IP-Address', op='==', value='192.168.2.1'