单项选择题
Which type of attack is characterized by flood of packet that requesing a TCP connection to a server?（）
A.denial of service B.brute force C.reconnaissance D.Trojan horse
单项选择题 Which item represents the standard IPACL？（）
单项选择题 What is the default routing update period for RIPv2?（）
多项选择题 The OSPF Hello protocol performs which of the following tasks (Choose two.)（）。
