Net+ Day 4 IP Addressing and Subnetting

A company wants to assign static IP addresses to 20 workstations in a new department. They also need to account for 2 printers and a server on the same network. Which of the following subnet masks would be the MOST appropriate choice for this scenario?

• /24
• /27
• /28
• /30

Answer explanation

/27 provides 30 usable addresses which is sufficient for the 23 devices needed.

A network administrator is configuring a new network with the IP address 192.168.1.0 and a subnet mask of 255.255.255.224. What is the broadcast address for this subnet?

• 192.168.1.31
• 192.168.1.63
• 192.168.1.127
• 192.168.1.15

Answer explanation

The broadcast address is found by inverting the last octet of the usable IP addresses (determined by the subnet mask) and adding 1.

A technician is troubleshooting a network connectivity issue. They discover a device with the IP address 10.0.1.45 and a subnet mask of 255.0.0.0. The network router has an IP address of 10.0.2.1. Why can't this device communicate with the router?

• The subnet mask is incorrect.
• The IP address is outside the network range.
• Different subnet masks are being used.
• Device has a default gateway mismatch.

Answer explanation

The subnet mask 255.0.0.0 defines a /8 network which creates a very large network class. The device and router are likely on different subnets.

A network administrator needs to configure a guest network with a limited number of devices (around 10). They want to isolate this network from the main company network. Which of the following IP address and subnet mask combinations would be MOST suitable?

• 10.0.0.1 /24
• 172.16.1.0 /16
• 192.168.0.0 /28
• 10.10.1.0 /23

Answer explanation

/28 provides 14 usable addresses which is more than enough for 10 devices and falls within the private IP range.

A technician is reviewing network documentation and sees an IP address of 172.17.30.1 with a subnet mask of 255.255.255.128. How many usable IP addresses are available on this subnet?

• 62
• 30
• 126
• 14

Answer explanation

With 7 bits allocated for the host portion (2^7 - 2), there are 126 usable addresses.

A network administrator is designing a new network and needs to accommodate 100 devices. They are limited to using the IP address block 192.168.10.0. Which subnet mask would provide the most usable addresses while maintaining manageability?

• /22
• /23
• /24
• /25

Answer explanation

/25 offers 126 usable addresses which is more than enough for 100 devices while keeping the number of subnets manageable.

You are configuring a new printer for your home network. The printer has a pre-configured static IP address of 192.168.0.100 and a subnet mask of 255.255.255.0. Your computer automatically obtains an IP address via DHCP. Will the printer be able to communicate with your computer?

• No, the subnet mask is incorrect for a home network.
• The IP address is outside the standard private range.
• Different subnet masks are being used.
• The printer needs to be configured for DHCP.

Answer explanation

A subnet mask of 255.255.255.0 creates a /24 network, which is a large classful network but is still suitable for a typical home network.However, devices need to be on the same subnet to communicate.

You have a network ID of 10.1.1.0 and a subnet mask of 255.255.255.192. What is the first usable host IP address?

• 10.1.1.1
• 10.1.1.2
• 10.1.1.32
• 10.1.1.64

Answer explanation

The first usable IP address is the network address + 1. Since there are 6 bits allocated for hosts (2^6 - 2), the usable addresses range from .1 to .62.

A network engineer is designing a network for a school with separate subnets for the administration staff (20 devices) and classrooms (200 devices). They want to minimize wasted IP addresses. Which combination of subnets would be MOST efficient?

• Two /26 subnets
• One /24 and one /27 subnet
• One /23 and one /28 subnet
• Two /27 subnets

Answer explanation

/24 provides 254 usable addresses (more than needed for classrooms) and /28 offers 30 usable addresses (enough for admin). This minimizes wasted addresses.

A technician is troubleshooting a device that cannot connect to the internet. The device IP address is 172.16.0.20 with a subnet mask of 255.255.240.0. The default gateway is set to 172.16.1.1. What is the most likely cause of the issue?

• The subnet mask is incorrect.
• The IP address is outside the network range.
• Different subnet masks are being used.
• Device has a default gateway mismatch.

Answer explanation

The subnet mask defines a /20 network, creating a large VLSM network. The device and router are likely on different subnets due to the mismatch in subnet masks.