anti-spoofing (VERY URGENT !!!)

[freeradius]

Dear all   We have a MAX TNT nas and now we have problems with spoofed icmp-echo and echo-reply packages. To sole the problem we must enable the Ascend-Source-IP-Check VSA reply for users authenticated from free radius. So I modified the clints.conf file to :     client A.B.C.D {      secret = somesecret      shortname = max      Ascend-Source-IP-Check[96]=1 }   After change radius does not complains about the new line but in debug output (radiusd -x -x) i cant see anything about this durring user authentication.   Is my radius propertly configuerd to send  Ascend-Source-IP-Check ? If yes how I can verify ? If no how I can send this VSA from freeradius ? Please not that we have cisco boxes also as clients of free radius. How I can enable anti-spoofing for cisco dial-up users ?   Thanks   A. Lykiardopoulos