Disconnect idle user

[Yevgeny Kosarzhevsky]

Hi,

I am using pppd on linux nas. The client has connected, then after some 
time freeradius server has disappered on the network because of 
connection issue. The user disconnected when it was still down. Then, 
after freeradius came up the user wasn't able to login anymore because 
of simultaneous login check with error 691 on windows. Radius was 
reporting Reply-Message := "\r\nYou are already logged in - access 
denied\r\n\n"

How to make radius stop thinking the user is connected (like if no 
Acct-Interim-Update messages received in specified time).