<server_num> is the sequential number of the specified authentication server on the LDAP or Radius server list.
Without specifying any server, HPDU shows the authentication type and a list of both LDAP and Radius servers that have been configured.
When specifying a server, only that server's basic configuration is displayed, such as IP address and port number.
With the parameter "details" added, detailed information of the specified server is displayed, such as an LDAP server's bind DN and the login name attribute, or a Radius server's timeout and retries values.