I Single choice questions (11 questions in total, 100.0 points)

1[2009] FTP Transfer between client and server FTP Command, the connection used is ().
A,Based on TCP Control connection above
B,Based on TCP Data connection on
C,Based on UDP Control connection above
D,Based on UDP Data connection on

Correct answer: A
FTP uses TCP

2[2010]If the local domain name server has no cache,
When a host domain name of another network is resolved by recursive method,
The number of domain name request messages sent by user host and local domain name server is () respectively.
A,One, one
B,One or more
C,Multiple, one
D,Multiple, multiple

Correct answer: A
Answer analysis:

When using recursive query, if the local domain name server inquired by the user host does not know the IP address of the queried domain name, the local domain name server will continue to send query request messages to other root domain name servers as a DNS client, rather than allowing the user host to carry out the next query by itself. Therefore, in this method, the domain name request hops sent by the user host and the local domain name server are one.

3[2012]If the process of sending and receiving e-mail between user 1 and user 2 is shown in the figure below,
In the diagram①,②,③The application layer protocol used in each phase can be ().
A,
SMTP,SMTP,SMTP

B,
POP3,SMTP,POP3

C,
POP3,SMTP,SMTP

D,
SMTP,SMTP,POP3

Correct answer: D
Answer analysis:
SMTP is responsible for receiving mail
POP3 is responsible for sending emails
SMTP is still used between e-mail servers

4[2013] About SMTP In the description of the agreement, the correct one is ().

I. Only 7 bits are supported ASCII Code content

II. Support sending mail between mail servers

III. Support sending mail from user agent to mail server

IV. Support sending mail from mail server to user agent

A,
only I,II and III

B,
only I,II and IV

C,
only I,III and IV

D,
only II,III and IV

Correct answer: A my answer: A score: 9.0
Answer analysis:
SMTP is not responsible for sending mail to the host
That's what POP3 is responsible for

5[2014]40. Visit a university using a browser Web The protocol that cannot be used when the website home page is ().

A,
PPP

B,
ARP

C,
UDP

D,
SMTP

Correct answer: D
Answer analysis:
SMTP is the transmission and sending protocol of e-mail

The host may connect to the Internet service provider ISP using PPP protocol;

When the host only knows the IP of another host in the network, but does not know its MAC address, it can use ARP protocol to query the MAC address corresponding to the IP address of that host;

When the host accesses the Web site, if the DNS buffer of the host does not store the IP address of the corresponding domain name, it will use DNS protocol to query the IP address of the domain name, and DNS protocol is based on UDP protocol;

SMTP protocol is only used for the user agent in the user's computer to send mail to the mail server or between the mail servers. It is impossible to access the Web page simply.

6[2015]33. adopt POP3 When the protocol receives mail, the transport layer service type used is ()
A,No data transmission service with unreliable connection
B,Reliable data transmission service without connection
C,There are data transmission services with unreliable connections
D,Reliable data transmission service

Correct answer: D
TCP

7[2015] From a browser HTTP In the following description of the request message, the error is ().


A,
This browser requests browsing index.html

B,
index.html Store in www.test.edu.cn upper

C,
The browser requests a continuous connection

D,
The browser has been browsing www.test.edu.cn

Correct answer: C
Answer analysis:
All connections are close d, and no continuous connection is used.

The Connection in the HTTP request message indicates the Connection mode, the value Close indicates the non continuous Connection mode, and the value keep alive indicates the continuous Connection mode
The Cookie value is generated by the server. The Cookie header in the HTTP request message indicates that you have visited www.test.com edu. Cn server.

8[2016]It is assumed that all domain name servers use iterative query for domain name resolution. When H4 Access specification domain name is www.abc.xyz.com Domain name server 201.1.1.1 In the process of completing the domain name resolution, it may send DNS The minimum and maximum number of queries are () respectively.  

A,0，3

B,1，3

C,0，4

D,1，4

Correct answer: C
Answer analysis:

When the DNS information of the domain name is stored in the DNS cache of H4, there is no need to query any domain name server, so at least 0 DNS queries are issued;

In the worst case, you need to send DNS query requests to the local domain name server, root domain name server (. com), top-level domain name server (xyz.com) and permission domain name server (abc.xyz.com) iteratively, so you can send DNS queries up to 4 times.

9[2017]37. Direct packaging RIP,OSPF,BGP The protocols of the message are ().
A,TCP,UDP,IP
B,TCP,IP,UDP
C,UDP,TCP,IP
D,UDP,IP,TCP

Correct answer: D
OSPF is the content of network layer, mainly IP protocol

10[2017]40. About FTP In the description of the agreement, the error is ().
A,The data connection is closed after each data transmission
B,The control connection remains open throughout the session
C,Between server and client TCP 20 Establish data connection through port
D,Between client and server TCP 21 Establish control connection through port

Correct answer: C
Answer analysis:
By default, in the active mode, the FTP protocol is to establish a data connection between port 20 of the server and the port provided by the customer.

11[2018]No conversion required SMTP The content directly transmitted by the protocol is ().
A,JPEG graphical
B,MPEG video
C,EXE file
D,ASCII text

Correct answer: D
Answer analysis:

SMTP is originally designed to transmit ASCII code rather than binary data.