超星 - 自测题 ch2

单选题

The widely used port number of web application is( ).

A. 25
B. 20
C. 80
D. 53

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单选题

HTTP has a mechanism that allows a cache to verify that its objects are up to date. The mechanism is( ).

A. persistent connections
B. cookies
C. Web Caching
D. conditional GET

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单选题

In the following descriptions about persistent connection, which one is not correct?( )

A. The server leaves the TCP connection open after sending a response.
B. Each TCP connection is closed after the server sending one object.
C. There are two versions of persistent connection: without pipelining and with pipelining.
D. The default mode of HTTP uses persistent connection with pipelining.

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单选题

FTP uses two parallel TCP connections to transfer a file, there are( ).

A. control connection and data connection
B. receiving connection and sending connection
C. client connection and sever connection
D. program connection and process connection

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单选题

If the status code in HTTP response message is 404, it means( ).

A. Request succeeded.
B. The requested document doesn’t exit on this server.
C. This is a generic error code indicating that the request could not be understood by the server.
D. Requested object has been permanently mover.

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单选题

DNS means ( ).

A. Data Name System
B. Data National System
C. Domain Name System
Domain National System

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单选题

There are three classes of DNS server except ( ).

A. Root DNS server
B. Local DNS server
C. TLD server
D. Authoritative DNS server

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单选题

The time it takes for a small packet to travel from client to server and then back to the client is ( ).

A. round-travel time
B. next-hop time
C. round-trip time
D. prefix-matching time

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单选题

In the four following options, which protocol is included in Mail Access Protocol?( )

A. TCP
B. DHCP
C. IMAP
D. FTP

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单选题

In the following options about C/S architecture, which is not correct?( )

A. In C/S architecture, there is an always-on host, called the server.
B. In C/S architecture, there is an always-on host, called the client.
C. The server has a fixed, well-known address, called IP address.
D. Clients do not directly communicate with each other.

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