Chapter 8

Question 1

The 4 fundamental functions of access control systems:

Answer 1

1- Identification: I am a user of the system (ID number).

2- Authentication: I can prove I’m a user of the system (smart card).

3- Authorization: Here’s what I can do with the system.

4- Accountability: You can track and monitor my use of the system.

Question 2

What’s Firewalls?

Answer 2

combination of hardware and software that filters specific information from moving between the outside and the inside network.

Question 3

5 firewalls processing modes:

Answer 3

1- Packet filtering firewalls: checks the IP and destination, Direction, and TCP or UDP.

2- Application gateways: a device capable of functioning both as a firewall and a proxy server.
- proxy servers are exposed to higher levels of risk from less trusted networks.

3- MAC layer firewalls: makes filtering decisions based on host computer’s identity.
- operates at the media access control sublayer(Layer 2).

4- Hybrid Firewalls: Combine elements of other types of firewalls.

Question 4

3 Firewalls architectures:

Answer 4

1- Single bastion hosts (sacrificial host): stands as a sole defender.
- contains two NICs, and connects to both the external and internal networks.
By using network address translation (NAT), it adds an extra layer of defense.

2- Screened host: Combines packet-filtering router with a separate, dedicated firewall such as an application proxy server (2 separate systems).
- Allows router to pre-screen packets to minimize the traffic/load on internal proxy.

3- Screened subnet (with DMZ):
- Dominant architecture used today.
- consists of multiple internal firewalls behind a packet-filtering router.

Question 5

What’s “content filters”?

Answer 5

software program allows administrators to restrict content that comes into or leaves a network.
- Primary purpose to restrict internal access to external material.

Question 6

What’s “RADIUS”?

Answer 6

is a system to authenticates users who are trying to access an organization’s network via a dial-up
connection.
centralizes responsibility for user authentication in a central RADIUS server.

Question 7

define VPN:

Answer 7

private network that uses the public telecommunications infrastructure to create a means for private communication.

Question 8

define VPN tunnel:

Answer 8

an encrypted Link between two private networks on the internet

Question 9

define tunneling:

Answer 9

allows the secure movement of data from one private network to another while using public network connectivity.

Question 10

2 types of tunneling:

Answer 10

1- Encryption: encoding information so only authorized parties can access it.

2- Encapsulation: wrapping an internet data packet inside of another packet (used to hide the IP Address of the user).

Question 11

Explain 4 types of VPN:

Answer 11

1- Remote Access VPN: Allows a user to connect to a private network and access its services remotely.
(Used to bypass regional restrictions on the internet)

2- Site-to-Site VPN [Router-to-Router VPN]: One router acts as a VPN Client and another router as a VPN Server.
- Within a company => Intranet-based VPN
- Company to company => Extranet-based VPN

3- Transport mode VPN: Data within IP packets are encrypted, but header information is not.

4- Tunnel mode VPN: Entire client package is encrypted; intercepted packet reveals nothing about the true destination system.