This method uses for PPPoE-Server with low signal to client (such as PPPoE Hotspot). when client get low signal . client always disconnect  from PPPoE dialup but user at PPPoE-Server still alive. so client can not connect to server. they must wait until server is clear the user.

this Freeradius unlang to clear user on server when client login again.

i setup on

Ubuntu 9.04 server i386

rp-pppoe 3.10

freeradius 2.1.0

ppp 2.4.5

add this line to your /etc/freeradius/site-enabled/default

on authorize section.

authorize {

#

#  The preprocess module takes care of sanitizing some bizarre

#  attributes in the request, and turning them into attributes

#  which are more standard.

#

#  It takes care of processing the 'raddb/hints' and the

#  'raddb/huntgroups' files.

#

#  It also adds the %{Client-IP-Address} attribute to the request.

preprocess

#Clear UserName

if (User-Name){  

"%{sql: UPDATE radacct set AcctTerminateCause='Clear-User',AcctStatusType='Stop',AcctStopTime=last_update WHERE UserName='%{User-Name}' and AcctStatusType!='Stop' and  CallingStationId='%{Calling-Station-Id}'}" 

}