Chapter 23: Network Security and Threats

Question 1

What is a firewall?

Answer 1

Prevents unauthorised access to a network or computer system via the internet.

Question 2

What is another name of packet filtering?

Answer 2

Static filtering

Question 3

What does packet filtering do?

Answer 3

Controls access of data packets to network, by inspecting source and destination IP addresses found in the header, and comparing to admin policies/rules.

Can also block packets depending on the port they try to access and protocols they use.

Question 4

What is dynamic packet filtering (stateful inspection)?

Answer 4

Analyses data packets by recording,

• state of active connections,
• IP addresses, and
• port number.

The data packet may be rejected if coming from unknown source.

Question 5

What does a proxy server do?

Answer 5

Intercepts all packets entering and leaving a network, hiding the true network address of the source from recipient.

• Enables privacy/anonymity.

Can hold cache of frequently visited websites to eliminate need for re-request from web page server.

• Speeds up user access to web page data and reduces web traffic.

Can filter requests using admin privileges and log user data to requests.

Exists between client and server, intercepting traffic and network from outside world.