Hi everyone Thanks for all the help and advice so far :-) I have installed freeradius 1.1.7 and get the appended message when I try to use it as a proxy between a Linux/Moodle/PHP radius client and a Windows IAS server. The shared secrets are definitely the same. The Linux/Moodle/PHP radius client authenticates directly with the Windows IAS server without any problems, but it will not authenticate with the freeradius proxy in between! I need a working freeradius proxy. Help... Clive Sending Access-Request of id 0 to 10.200.0.2 port 1812 NAS-Identifier = "vle.bromley.ac.uk" NAS-Port-Type = Virtual Service-Type = Framed-User Framed-Protocol = PPP Calling-Station-Id = "127.0.0.1" User-Name = "cliveg@staff.bromley.local" MS-CHAP2-Response = removed from message MS-CHAP-Challenge = removed from message NAS-IP-Address = 10.200.0.14 Proxy-State = 0x3832 --- Walking the entire request list --- Waking up in 6 seconds... rad_recv: Access-Accept packet from host 10.200.0.2:1812, id=0, length=235 Received Access-Accept packet from client 10.200.0.2 port 1812 with invalid signature (err=2)! (Shared secret is incorrect.) Dropping packet without response.