D-Link DES-3550 Command Line Interface Reference Manual page 259

config authen_login
Restrictions
Only administrator-level users can issue this command.
DES-3550 Layer 2 Fast Ethernet Switch
TACACS protocol from a remote TACACS server.
xtacacs – Adding this parameter will require the user to be authenticated using the
XTACACS protocol from a remote XTACACS server.
tacacs+ – Adding this parameter will require the user to be authenticated using the
TACACS+ protocol from a remote TACACS+ server.
radius - Adding this parameter will require the user to be authenticated using the
RADIUS protocol from a remote RADIUS server.
server_group <string 15> - Adding this parameter will require the user to be
authenticated using a user-defined server group previously configured on the
Switch.
local - Adding this parameter will require the user to be authenticated using the
local user account database on the Switch.
none – Adding this parameter will require no authentication to access the Switch.
NOTE: Entering none or local as an authentication protocol will override any other
authentication that follows it on a method list or on the default method list.
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