A.An HTTP SDF file location can be specified by clicking the Add button.
B.If all specified SDF locations fail to load， the signature file that is named default.sdf will be loaded.
C.The Autosave feature automatically saves the SDF alarms if the router crashes.
D.The Autosave feature is automatically enabled for the default built-in signature file.
E.The name of the built-in signature file is default.sdf.
F.The Use Built-In Signatures （as backup） check box is selected by default.