📘 Chapter 4 – Network Security Devices, Design & Technology

Q: How can network security be achieved?

A: By using security features in standard network devices and dedicated security hardware.

Q: Why is the OSI model important for security devices?

A: Security devices function at different OSI layers, each providing specific protections.

Q: What risk do improperly configured devices create?

A: They introduce vulnerabilities.

Q: What is a bridge?

A: A device that connects two network segments and work at the Layer 2 (Data Link).

Q: Why can software bridges be risky?

A: They may unintentionally expose networks.

Q: What is the function of a switch?

A: Intelligently forwards frames based on MAC addresses and uses MAC address table.

Q: Why are switches more secure than hubs?

A: They send data only to intended recipients.

Q: What is a MAC flooding attack?

A: Overloading a switch with fake MAC addresses.

Q: What defense prevents MAC flooding?

A: Flood guard (port security).

Q: What is the main function of a router?

A: Forward packets between networks and works at Layer 3 of OSI which is Network.

Q: How do routers enhance security?

A: Using Access Control Lists (ACLs).

Q: What is the purpose of a load balancer?

A: Distribute traffic evenly across servers.

Q: Two advantages of load balancing?

A:

• Prevents server overload

• Optimizes bandwidth

Q: What are Layer 4 load balancers?

A: Use Network and Transport layer data.

Q: What are Layer 7 load balancers?

A: Use Application layer data.

Q: What is a proxy server?

A: Intermediary that processes requests on behalf of users.

Q: What is a forward proxy?

A: Intercepts internal user requests.

Q: What is a reverse proxy?

A: Routes external requests to internal servers.

Q: What is a transparent proxy?

A: Requires no user configuration.

Q: Benefits of proxy servers?

A:

• Increased speed

• Reduced cost

• Improved management

• Stronger security

Q: What is a firewall?

A: A device that inspects and filters network traffic.

Q: Types of firewalls?

A:

• Hardware firewalls

• Software (host-based) firewalls

Q: Which firewall protects a single device?

A: Software firewall.

Q: What is stateless packet filtering?

A: Filters packets individually based on rules.

Q: What is stateful packet filtering?

A: Tracks active connections before allowing traffic.

Q: What does “Allow” mean in firewall rules?

A: Packet is permitted.

Q: What does “Drop” mean?

A: Packet is silently discarded.

Q: What does “Reject” mean?

A: Packet is blocked and sender is notified.