Network Segmentation

CIDR Block Notation

1. What is CIDR notation? a CIDR block?

• A CIDR Block is a range of IP addresses set up to be used within a network and CIDR notation is a a way of representing that block.

2. How many octets are found in an IPv4 address?

• 4

3. Setting binary aside and using the decimal system, what is the range of numbers found in an octet?

• 0-255

4. What does the final digit after the “/” represent in an IPv4 address?

• The subnet mask, which determines how many octets are set aside for the CIDR block.

5. How many IP addresses are in the CIDR block 10.0.0.0/24?

• 65,356

Source: Michael Nicholas

Network Segmentation

1. In your own words, describe network segmentation.

• Network segmentation is a means of protecting networks from malware/intrusion creep by utilizing physical and virtual means of separating network assets and branches from each other.

2. Network segmentation isn’t important as long as the network is using a well configured firewall. Do you agree? Why or why not?

• No. Layered security, aka security in depth, is always preferable. Relying on a firewall creates a single point of security failure. Once it is breached, there is nothing let to stop a cybercriminal from doing whatever they want within the system.

3. What is a screened subnet?

• Setting up public networks separate from from the secured LAN used for private business functions so public users can't make the jump from the public side to the critical business functions side.

4. Cameras, ID card scanners, locked doors and biometrics are just a few examples of what type of security?

• Traditional physical security.

Source:CompTIA