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
In the four following options, which protocol is included in Mail Access Protocol?( )
A. TCP
B. DHCP
C. IMAP
D. FTP
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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