第二期七章
1、A client is communicating with a server on a different segment of the network. How does the server determine确定what service is being requested by the client?确定提供的网络
applies the default service configured in directory services
uses ARP to discover the appropriate service from the local router
sends a request to the client asking for the appropriate service
identifies the appropriate service from the destination port field目的端口号
2、What is the function of the TCP three-way handshake?
It enables the synchronization of port numbers between source and destination hosts.
It immediately triggers the retransmission of lost data.
It synchronizes同步both ends of a connection by allowing both sides to agree upon initial sequence numbers. 双方议定/协商初始序列号
It identifies the destination application on the receiving host.
3、What are three unique characteristics of UDP? (Choose three.) connection oriented
full-duplex operation
low overhead 低开销
no flow control 无流量控制
no error-recovery function 错误不重传
reliable transmission
4、Within TCP, what combination 组件makes up a socket pair对? 套接对source port with destination port
source IP address with destination port
source IP address and destination IP address
source IP address and port with a destination IP address and port
5、What type of update allows client computers to register注册and update their resource records 原纪录with a DNS server whenever changes occur? dynamic
zone transfer
local recursive query
root domain query
top-level domain query
6、Which DNS zone resolves 解析an IP address to a qualified domain name 一个合格的域名?
dynamic lookup
forward lookup
resolution lookup
reverse lookup 反向查找
7、Which two tasks are the responsibility of the local DNS server? (Choose two.)
maintaining a large number of cached DNS entries
maintaining the ISP server
mapping name-to-IP addresses for internal hosts 内部主机的域名-IP映射
forwarding name resolution解析requests to a caching-only server 将域名解析请求转发至只有缓存功能的服务器
forwarding all name resolution requests to root servers on the Internet
8、Which protocol is used to send e-mail, either from a client to a server or from a server to another server?
SNMP
FTP
SMTP
HTTPS
9、A manufacturing company subscribes to certain hosted services from their ISP. The services required include hosted world wide web, file transfer, and e-mail. Which protocols represent these three key applications?
(Choose three.)
FTP
HTTP
DNS
SNMP
DHCP
SMTP
10、To meet customer expectations满足客户期望, an ISP must guarantee确保a level of service that is based on what two factors? (Choose two.)
accessibility
adaptability
availability 可用性
reliability 可靠性
scalability
11、Which two statements are true about the OSI and TCP/IP models? (Choose two.)
The two bottom layers of the TCP/IP model make up the bottom layer of the OSI model.
The TCP/IP model is a theoretical model and the OSI model is based on actual protocols.
The OSI network layer is comparable相当于to the Internet layer of the TCP/IP model.
The TCP/IP model specifies protocols for the physical network interconnection.
The TCP/IP model is based on four layers and the OSI model is based on seven layers.
12、What type of DNS server is typically maintained by an ISP?
caching-only 缓存
root
second-level
top-level
13、Which two options correctly match protocol and well-known port number协议和端口的匹配? (Choose two.)
DNS - 25
FTP - 110
HTTP - 80
POP3 - 25
SMTP - 25
14、What are three characteristics of HTTPS? (Choose three.)
It uses a different client request-server response process than HTTP uses. It specifies additional rules for passing data between the application and data link layers.
It supports authentication.
It allows more simultaneous connections than HTTP allows.
It encrypts packets with SSL.
It requires additional server processing time.额外的服务器处理时间15、User1 is sending an e-mail to User2@https://www.doczj.com/doc/9817852816.html,. What are two characteristics of the process of sending this data? (Choose two.)
It utilizes TCP port 110.
A TCP connection is established directly between the User1 and User2 client computers in order to send the e-mail message.
It utilizes利用a store and forward process. 使用存储转发
The same application layer protocol is used to send the e-mail and retrieve it from the destination server.
SMTP is used to send the e-mail message to the mail servers.
16、Which three fields do a TCP header and a UDP header have in common? (Choose three.)
source port
window
checksum 校验和
destination port
acknowledgment number
sequence number
17、When a host is communicating with multiple applications on the same server at the same time, which two values will likely be the same in all packets for each session? 那个保持一致的(Choose two.)
IP address
MAC address
session number
sequence number
18、What are three characteristics of network reliability可用性? (Choose three.)
Redundant冗余hardware provides enhanced reliability. 硬件冗余提供提高可靠性。
Reliability is measured based on the number of applications in use on the network.
The longer the MTTR, the greater the reliability.
Fault tolerance is a measure of reliability. 可用容错能力来衡量可靠性
The longer the MTBF, the greater the reliability.
An ISP guarantees the same level of reliability to all of its customers.
19、Refer to the exhibit. Host1 is in the process of setting up a TCP session with Host2. Host1 has sent a SYN message to begin session establishment. What happens next?
Host1 sends an ACK message to Host2.
Host1 sends a SYN message to Host2.
Host1 sends a SYN-ACK message to Host2.
Host2 sends an ACK message to Host1.
Host2 sends a SYN message to Host1.
Host2 sends a SYN-ACK message to Host1.
20、Refer to the exhibit. The PC is requesting HTTP data from the server. What is a valid representation of source and destination sockets for this request?源和目的套接
Source - 192.168.1.17:80 ; Destination - 192.168.2.39:80
Source - 192.168.1.17:80 ; Destination - 192.168.2.39:1045
Source - 192.168.1.17:1045 ; Destination - 192.168.2.39:80
Source - 192.168.1.17:1045 ; Destination - 192.168.2.39:1061
21、Refer to the exhibit. Which two statements are true about this file? (Choose two.)
If the gateway address changes, the file will be updated dynamically.
The command ping fileserv will use IP address 172.16.5.10.
If the ping https://www.doczj.com/doc/9817852816.html, command is issued, the file will be checked for the Cisco web server IP address before DNS is queried. 在进行DNS请求前，将检查该文件中的Cisco web服务器IP 地址。
The command ping mypc will use IP address 172.16.5.1.
Name to IP address mappings are added to the file after they are received from DNS.
22、Which two statements describe the FTP protocol? (Choose two.)
It uses well-known port 23.
The protocol interpreter is responsible for the data transfer function.
The FTP client initiates the transfer of data会启动数据传输when using a passive data connection.
It requires two connections between client and server.
FTP servers open a well-known port on the client machine.