多项选择题
Which fields are included in the TCP header?（）
A. Source Port B. Acknowledgement Number C. Request Number D. Destination Address E. Window F. Data
单项选择题 How many simultaneous Telnet sessions does a Cisco router support by default?（）
单项选择题 Which of the following protocols use both TCP and UDP ports?（）
多项选择题 What statements are true regarding ICMP packets?（）
