单项选择题
Which of the following is used by RADIUS to encrypt messages between the server and the client?（）
A. Public key B. CSU/DSU C. Private key D. Shared secret
单项选择题 Which of the following is an EGP routing protocol?（）
单项选择题 At which of the following layers does the TFTP protocol operate?（）
单项选择题 Which of the following is a multifunction device in a SOHO network?（）
