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Column series: multiple-choice questions for written examinations
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Preface
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1.
Analysis: A
Question analysis:
Knowledge point analysis:
Option A: DNS hijacking, also known as domain name hijacking, refers to intercepting domain name resolution requests within the hijacked network range, analyzing the requested domain name, and releasing requests outside the scope of review, otherwise a fake IP address or nothing will be returned. Failure to do so will cause the request to become unresponsive. The result is that the specific network cannot respond or the accessed URL is a fake URL.
Option B: DDoS attack: Distributed Denial of Service (DDoS: Distributed Denial of Service) attack refers to using client/server technology to unite multiple computers as an attack platform to launch DDoS attacks on one or more targets, thereby multiplying greatly increase the power of denial of service attacks.
Option C: MAC address spoofing: Use mac spoofing to prevent any computer in the LAN from using the network.
Option D: Fake DHCP server: It is essentially a DHCP spoofing attack, which exhausts the IP resources of the real DHCP server, and then deploys a fake DHCP server to allow the host to request from the fake DHCP server.
2.
Analysis: B
Question analysis:
Three-way handshake and four-way wave process:
3.
Analysis: D
Question analysis:
1.TCP itself is a reliable transmission protocol, supporting retransmission, error correction, network congestion processing, etc.;2. TCP itself is a byte stream-oriented protocol and does not care much about the format of the payload sent. The application layer protocol handles the format of the sent data, and the application layer protocol is considered and processed by the programmer (tcp sticky packet The same is true for the problem)
4.
Parsing: C
Question analysis:
1. HTTPS adds SSL to the foundation of HTTP. The security foundation of HTTPS is SSL, so the details of encryption require SSL.
2. Use SSL for encrypted transmission of data transmitted using HTTP. Even if a third party obtains the content of the data packet from the network, it will not be able to parse the transmitted content because there is no encryption key, thereby achieving the encryption effect.
5.
Parsing: C
Question analysis:
Three-way handshake and four-way wave process:
6.
Analysis:
7.
Analysis:
8.
Analysis:
Question analysis:
Knowledge point analysis:
POP3 protocol
1. POP3 is the mail protocol version 3, which is a member of the TCP/IP protocol family;2. This protocol is primarily used to support remote management of email on the server using a client. The POP3 protocol that provides SSL encryption is called POP3S
3. It belongs to the application layer protocol, and the transport layer protocol uses the TCP protocol, so it is a protocol with reliable links;
9.
Analysis: B
Question analysis:
I, III: UDP is an unreliable, connectionless, datagram-oriented protocol. There is a 16-byte checksum in the protocol header, which can verify whether the data is distorted during transmission, but there is no guarantee. reliable.
II: Transport layer decentralization and multiplexing is to extend the host-to-host transmission service provided by the network layer to the transmission service between application processes running on the computer, that is, point-to-point transmission. The point here can be understood as a port;
Decentralization: It is a service that sends the information in the transport layer segment to the correct socket;
Multiplexing: The data in all sockets is concentrated and encapsulated with header information, and then sent to the network layer service;
10.
Analysis:
Summarize
