如果该国在2003年第一季度的居民消费支出总额为24.3亿美元，则本年度第四季度居民的消费支出应与

A.The Mac address of the NIC in Sever1

B.The IP address of Server 1.

C.The MAC address of the s0/0/0 interface of router R2

D.The IP address of the s0/0/0 interface of router R1

E.The IP address of the Fa0/0 interface of router R1

A.向目标主机发送UDP Echo Request数据包，等待对方回应UDP Echo Reply数据包

B.向目标主机发送ICMP Echo Request数据包，等待对方回应ICMP Echo Reply数据包

C.向目标主机发送UDP Echo Reply数据包，等待对方回应ICMP Echo Request数据包

D.向目标主机发送ICMP Echo Reply数据包，等待对方回应ICMP Echo Request数据包

A．Echo request and Echo reply

B．ICMP hold and ICMP send

C．ICMP request and ICMP reply

D．Echo off and Echo on

E．None of the above

A.Host 1 addresses the frames to the MAC address of router R1

B.Host 1 looks in its ARP cache for the MAC address of router R1

C.Host 1 addresses the frames to the MAC address of web server 2

D.Host 1 sends the packets to router R1 to be forwarded to web server 2

E.Host 1 sends a broadcast ARP request to obtain the MAC address of webserver2

A．icmp

B．icmp=8

C．icmp[0]=8

D．icmp[0]=0

A. ICMP echo request

B. Information interrupt request

C. Timestamp reply

D. Source quench

E. None of the above

A．echo 0>/proc/sys/net/ipv4/icmp（）echo（）ignore（）all

B．echo 1>/proc/sys/net/ipv4/icmp（）echo（）ignore（）all

C．echo 0>/proc/sys/net/ipv4/tcp（）syncookies

D．echo 1>/proc/sys/net/ipv4/ tcp（）syncookies

A.Source quench

B.Echo request 和Echo reply

C.Destination unreachable

D.Redirect

A．报告错误

B．检查节点（node）之间的通达性

C．检查IP分组的生存时间

D．发现IP地址

A.Router C will use ICMP to inform Host 1 that Host 2 cannot be reached.

B.Router C will use ICMP to inform Router B that Host 2 cannot be reached.

C.Router C will use ICMP to inform Host 1, Router A, and Router B that Host 2 cannot be reached.

D.Router C will send a Destination Unreachable message type.

E.Router C will send a Router Selection message type.

F.Router C will send a Source Quench message type.