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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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.
DNS means ( ).
A. Data Name System
B. Data National System
C. Domain Name System
Domain National System
There are three classes of DNS server except ( ).
A. Root DNS server
B. Local DNS server
C. TLD server
D. Authoritative DNS server
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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