The order of the authentication server list determines the access priority of remote authentication servers. The PXE first tries to access the top server in the list for authentication, then the next one if the access to the first one fails, and so on until the PXE device successfully connects to one of the listed servers.
Note: After successfully connecting to one external authentication server, the PXE STOPS trying to access the remaining authentication servers in the list regardless of the user authentication result.