Subnetting

What is subnetting?

• The process of breaking down an IP address into smaller networks

• The process of combining multiple IP addresses into a single network

• The process of converting an IP address into a domain name

• The process of securing a network against cyber attacks

Answer explanation

Subnetting involves dividing a larger network into smaller, more manageable sub-networks. This is achieved by using a subnet mask to define the network boundary and assign unique IP addresses to each host on the network.

What is a subnet mask?

• A 32-bit binary number that identifies a network and host address

• A 48-bit binary number that identifies a MAC address

• A 16-bit binary number that identifies a network address

• A 24-bit binary number that identifies a host address

Answer explanation

The subnet mask is used to determine the network portion and host portion of an IP address. It is a 32-bit binary number that has 1s in the network portion and 0s in the host portion.

What is a subnet?

• A group of IP addresses that share the same network portion

• A group of IP addresses that share the same host portion

• A group of devices that share the same network interface card

• A group of devices that share the same MAC address

Answer explanation

A subnet is a logical division of a larger network. It consists of a group of IP addresses that share the same network portion, which is defined by the subnet mask

What is the purpose of subnetting?

• To reduce the number of hosts on a network

• To increase the security of a network

• To improve network performance and efficiency

• To simplify network management

Answer explanation

Subnetting allows for better utilization of network resources by reducing the size of broadcast domains and limiting the scope of network traffic. This can lead to improved network performance and efficiency.

What is CIDR notation?

• A method of representing IP addresses and subnet masks

• A method of assigning IP addresses to hosts

• A method of encrypting network traffic

• A method of mapping domain names to IP addresses

Answer explanation

Classless Inter-Domain Routing (CIDR) notation is a method of representing IP addresses and subnet masks using a combination of the IP address and a prefix length. For example, the IP address 192.168.1.0 with a subnet mask of 255.255.255.0 can be represented as 192.168.1.0/24 in CIDR notation.

What is the maximum number of subnets that can be created from a Class C network?

• 2

• 4

• 8

• 16

Answer explanation

A Class C network has 24 network bits and 8 host bits. By using the host bits for subnetting, up to 8 subnets can be created.

What is the maximum number of hosts that can be assigned to each subnet in a Class B network with a subnet mask of 255.255.240.0?

• 254

• 510

• 1022

• 2046

Answer explanation

A Class B network has 16 networkbits and 16 host bits. A subnet mask of 255.255.240.0 uses 12 bits for subnetting, leaving 4 bits for hosts. Therefore, each subnet can have up to 2^4 - 2 = 14 hosts (2 for network and broadcast addresses), but in practice, it is recommended to use a smaller number of hosts for better network performance.

Which of the following is NOT a valid private IP address range?

• 10.0.0.0 - 10.255.255.255

• 172.16.0.0 - 172.31.255.255

• 192.168.0.0 - 192.168.255.255

• 169.254.0.0 - 169.254.255.255

Answer explanation

The range 169.254.0.0 - 169.254.255.255 is reserved for Automatic Private IP Addressing (APIPA) and is used by hosts when they are unable to obtain an IP address from a DHCP server. It is not considered a valid private IP address range for subnetting purposes.

What is the default subnet mask for a Class A network?

• 255.0.0.0

• 255.255.0.0

• 255.255.255.0

• 255.255.255.255

Answer explanation

A Class A network uses the first octet to identify the network portion and has 8 network bits and 24 host bits. The default subnet mask for a Class A network is 255.0.0.0, which means that the first octet identifies the network and the remaining 3 octets identify the host portion.

What is the purpose of VLSM?

• To simplify network management by using fixed-length subnet masks

• To increase network security by using longer subnet masks

• To conserve IP addresses by using variable-length subnet masks

• To improve network performance by using shorter subnet masks

Answer explanation

Variable-Length Subnet Masking (VLSM) allows for more efficient use of IP addresses by using subnet masks of different lengths for different subnets within the same network. This can help conserve IP addresses and reduce waste.