思科认证的学习在一定程度上难度较大，更多的是在于练习和阅读。为了帮助广大考生系统全面的复习好《思科认证：CCNA认证学科》，我们考吧网整理了思科认证模拟试题，本次汇编的模拟试题希望对你的考试有所帮助，预祝你考试顺利。

1. What type of segment and data is shown in the graphic? (5)

1) a UDP segment carrying e-mail traffic

2) a TCP segment carrying FTP traffic

3) an IP segment carrying FTP traffic

4) a UDP segment carrying web traffic

5) a TCP segment carrying web traffic

6) an IP segment carrying e-mail traffic

2. What is the purpose of using port numbers in the transport layer? (4)

1) to identify the segment as being either TCP or UDP

2) to provide reliability during data transport

3) to identify the interface port number used by the router when forwarding data

4) to track multiple conversations that occur between hosts

3. Which transport layer unit of information places the port number in the header? (2)

1) data

2) segment

3) packet

4) frame

5) bit

4. Which of the following describes a type of denial of service attack designed to exploit the normal function of the TCP three-way handshake? (1)

1) A host sends a packet with a spoofed source IP address.

2) A host sends a packet with an incorrect destination IP address.

3) A source sends a packet containing a garbled header.

4) A host sends an oversized packet that fills the memory buffers of the destination host.

5) A host sends a packet that contains a virus.

6) A host sends a packet that contains a worm.

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思科认证：CCNA认证考前精选模拟试题汇总三

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