試題1

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試題2

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試題3

Network Addres Translation(NAT) is an Internet standard that enbles a local-area network to use one set of IP addresses for internet traffic and another set of ( ) IP addresses for external traffic. The main use of NAT is to limit the number of public IP addresses that an organization or company must use, for both economy and ( ) purposes. NAT remaps an IP address space into another by modifying network address information in the ( ) header of packets while they are in transit across a traffic routing device. It has become an essential tool in conserving global address space in the face of ( ) address exhaustion. When a packet traverses outside the local network, NAT converts the private IP address to a public IP address. If NAT runs out of public addresses，the packets will be dropped and ( )"host unreachable"packets will be sent.
(1) A. local
B. private
C. public
D. dynamic
(2) A. political
B. fairness
C. efficiency
D. security
(3) A.MAC
B. IP
C.TCP
D. UDP
(4) A. IPv4
B. IPv6
C. MAC
D. logical
(5) A. BGP
B. IGMP
C. ICMP
D. SNMP

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試題4

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試題5

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試題6

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試題7

安全電子郵件協(xié)議PGP不支持  （ ）  。
A、確認發(fā)送者的身份
B、確認電子郵件未被修改
C、防止非授權者閱讀電子郵件
D、壓縮電子郵件大小

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試題8

下圖所示為一種數(shù)字簽名方案，網(wǎng)上傳遞的報文是  (1)  ，防止A抵賴的證據(jù)是  (2)  。



（1）A、P
B、DA(P)
C、EB(DA(P))
D、DA
（2）A、P
B、DA(P)
C、EB(DA(P))
D、DA

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試題9

設信道采用2DPSK調制，碼元速率為300波特，則最大數(shù)據(jù)速率為?。?）　b/s。
A、300
B、600
C、900
D、1200

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試題10

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