For MA5200F attached 802.1x and pppoe service, user address allocation uses remote DHCP server to analyze address.Authentication is normal but address allocation fails.
DHCP server is down or IP remote pool is full.
1. Ping dhcp-server at MA5200F console and it communicates. It indicates that the physical cable between MA5200F and DHCP server is normal.
2. Check remote address pool configuration at MA5200F and dhcp-server, they are normal.
3. Configure local address pool of the same address segment, and then user address allocation succeeds.
4. Use local address pool and user can allocate address, but user cannot access external network. Device at upstream at MA5200F does not configure return route of user network segment.
5. Add return route of user network segment at device at upstream at MA5200F, user can access network. Test remote address pool, and it is found that IP address can be allocated from remote DHCP server.
When MA5200F enables dhcp relay, the source address of sending DHCP packet is gateway of remote address pool. Device at upstream has no return route of user network segment. DHCP response packet cannot respond MA5200F, so DHCP fails and user cannot obtain address.
When BAS, radius-server and dhcp-server interact, notice source address and destination address of interaction packet.