A. switch to switchB. switch to hubC. switch to routerD……

单项选择题A system administrator installed a new switch using a script to configure it. IP connectivity was tested using pings to SwitchB. Later attempts to access NewSwitch using Telnet from SwitchA failed. Which statement is true?（）

A. Executing password recovery is required.
B. The virtual terminal lines are misconfigured.
C. Use Telnet to connect to RouterA and then to NewSwitch to correct the error.
D. Power cycle of NewSwitch will return it to a default configuration.

单项选择题A host is attempting to send data to another host on a different network. What is the first action that the sending host will take?（）

A. Drop the data.
B. Send the data frames to the default gateway.
C. Create an ARP request to get a MAC address for the receiving host.
D. Send a TCP SYN and wait for the SYN ACK with the IP address of the receiving host.

单项选择题When two hosts are trying to communicate across a network, how does the host originating the communication determine the hardware address of the host that it wants to talk to?（）

A. RARP request
B. Show Network Address request
C. Proxy ARP request
D. ARP request
E. Show Hardware Address request

单项选择题Which network protocol does DNS use?（）

A. FTP
B. TFTP
C. TCP
D. UDP
E. SCP

单项选择题Which statement describes the process of dynamically assigning IP addresses by the DHCP server?（）

A. Addresses are allocated after a negotiation between the server and the host to determine the length of the agreement.
B. Addresses are permanently assigned so that the hosts uses the same address at all times.
C. Addresses are assigned for a fixed period of time, at the end of the period, a new request for an address must be made.
D. Addresses are leased to hosts, which periodically contact the DHCP server to renew the lease.