When user uses dialup, it indicates 738 false and user cannot obtain address.
1. Data configuration is correct.
2. There is idle address in address pool and no address conflict.
3. Check user online failure with display aaa online-fail-record and find User online fail reason: PPP user request.
4. Test PPP dial-up software and it is normal. Change PC test and the problem still exists.
5. Debug user's Radius authentication packet and find that Radius returns code 2 packets, but MA5200G does not send account request packet of code 4.
6. Analyze returned code 2 packets of Radius. Find Framed-IP-Address (8) attribute value is 0.0.0.0. It is designated IP address. But all 0 address is regarded as illegal by MA5200G. User debugs Radius and there is no problem.
Radius Received a Packet
Server Template: 0
Server IP : ××××××
Server Port : 1645
Code : 2
Len : 48
ID : 200
[Service-Type(6) ] [6 ] 
[Framed-Protocol(7) ] [6 ] 
[Framed-IP-Address(8) ] [6 ] [0.0.0.0]
User's IP address is flooded by Radius but the address is 0.0.0.0. MA5200 resognizes it as illegal, so user allocation address fails.
Turn on corresponding debug switch or use service traceing. When using address flooded by Radius, do not configure illegal address to users.