Network security fill in the blanks

Chapter 1

1. The three basic goals of information security are confidentiality, integrity and availability. In addition, there is another goal that can not be ignored: legal use.

2. There are four basic security threats in the network: information leakage, integrity destruction, denial of service and illegal use.

3. Access control policies can be divided into mandatory access control policies and autonomous access control policies.

4. Security * can be divided into passive * * and active * *.

5. The five types of security services defined by X.800 are authentication, access control, data confidentiality, data integrity and non-repudiation.

6. The eight specific security mechanisms defined by X.800 are: encryption, digital signature, access control, data integrity, authentication exchange, traffic filling, routing control and notarization.

7. The five common security mechanisms defined by X.800 are: trusted function, security flag, event detection, security audit tracking and security recovery.

Chapter 2

1. The IPv4 length of the host is 32b, and the MAC address length of the host is 48b. The address length of IPv6 is 128b.

2. The main function of ARP is to translate IP addresses into physical addresses.

3. The main function of NAT is to realize the translation between network address and IP address, which solves the problem of shortage of IPv4 address.

4. DNS service uses port 53, which is used to map domain name to IP address or IP address to domain name.