An NE40E-X8 is on the LNS side, and an ACS functions as the authentication server. The authentication server randomly receives some authentication packets with the NE40E-X8 user name every day. Because the authentication name is not found, these packets are rejected. On the authentication server, the displayed authentication user name is NE40E-03000000000000, which consists of a device name followed by a string of characters.
The BAS receives PAP authentication packets with an empty user name on the LAC side. By default, if the received packets do not carry a user name, the device constructs a user name. To prevent the device from sending packets that carry a constructed user name to the RADIUS server, run the ppp username check command.