11 - IPv4 Addressing

What is the prefix length notation for the subnet mask 255.255.255.224?

/27 Topic 11.1.0 - The binary format for 255.255.255.224 is 11111111.11111111.11111111.11100000. The prefix length is the number of consecutive 1s in the subnet mask. Therefore, the prefix length is /27.

Host-A has the IPv4 address and subnet mask 172.16.4.100 255.255.0.0. Which of the following IPv4 addresses would be on the same network as Host-A? (Choose all that apply)

172.16.4.99 172.16.0.1

Host-A has the IPv4 address and subnet mask 192.168.1.50 255.255.255.0. Which of the following IPv4 addresses would be on the same network as Host-A? (Choose all that apply)

192.168.1.1 192.168.1.100

What subnet mask is represented by the slash notation /20?

255.225.240.0 Topic 11.1.0 - The slash notation /20 represents a subnet mask with 20 1s. This would translate to: 11111111.11111111.11110000.0000, which in turn would convert into 255.255.240.0.

A network administrator is variably subnetting a network. The smallest subnet has a mask of 255.255.255.224. How many usable host addresses will this subnet provide?​

30 Topic 11.8.0 - The subnet mask 255.255.255.224 is equivalent to the /27 prefix. This leaves 5 bits for hosts, providing a total of 30 usable IP addresses (25 = 32 - 2 = 30).

Assigning an IPv4 address to a host requires the following:

IPv4 address - This is the unique IPv4 address of the host. Subnet mask- This is used to identify the network/host portion of the IPv4 address.

Within each network are three types of IP addresses:

Network address Host addresses Broadcast address

Which two statements are correct about public IPv4 addresses? (Choose two.)

To access a device over the internet, the destination IPv4 address must be a public address. Public IPv4 address exhaustion is a reason why there are private IPv4 addresses and why organizations are transitioning to IPv6.

Host addresses are...

addresses that can be assigned to a device such as a host computer, laptop, smart phone, web camera, printer, router, etc. The host portion of the address is the bits indicated by 0 bits in the subnet mask. Host addresses can have any combination of bits in the host portion except for all 0 bits (this would be a network address) or all 1 bits (this would be a broadcast address). All devices within the same network, must have the same subnet mask and the same network bits. Only the host bits will differ and must be unique.

A broadcast address is...

an address that is used when it is required to reach all devices on the IPv4 network.

What does the IP address 172.17.4.250/24 represent?

host address Topic 11.1.0 - The /24 shows that the network address is 172.17.4.0. The broadcast address for this network would be 172.17.4.255. Useable host addresses for this network are 172.17.4.1 through 172.17.4.254.

Which two parts are components of an IPv4 address? (Choose two.)

network portion host portion Topic 11.1.0 - An IPv4 address is divided into two parts: a network portion - to identify the specific network on which a host resides, and a host portion - to identify specific hosts on a network. A subnet mask is used to identify the length of each portion.

Which devices will not forward an IPv4 broadcast packet by default?

router

What is the purpose of the subnet mask in conjunction with an IP address?

to determine the subnet to which the host belongs Topic 11.1.0 - With the IPv4 address, a subnet mask is also necessary. A subnet mask is a special type of IPv4 address that coupled with the IP address determines the subnet of which the device is a member. ​

Host-A has the IPv4 address and subnet mask 10.5.4.100 255.255.255.0. What is the network address of Host-A?

10.5.4.0

Host-A has the IPv4 address and subnet mask 10.5.4.100 255.255.255.0. Which of the following IPv4 addresses would be on the same network as Host-A? (Choose all that apply)

10.5.4.1 10.5.4.99

If a network device has a mask of /28, how many IP addresses are available for hosts on this network?

14 Topic 11.1.0 - A /28 mask is the same as 255.255.255.240. This leaves 4 host bits. With 4 host bits, 16 IP addresses are possible, but one address represents the subnet number and one address represents the broadcast address. 14 addresses can then be used to assign to network devices.

Host-A has the IPv4 address and subnet mask 172.16.4.100 255.255.0.0. What is the network address of Host-A?

172.16.0.0

Which subnet mask would be used if 5 host bits are available?

255.255.255.224 Topic 11.1.0 - The subnet mask of 255.255.255.0 has 8 host bits. The mask of 255.255.255.128 results in 7 host bits. The mask of 255.255.255.224 has 5 host bits. Finally, 255.255.255.240 represents 4 host bits.

Which subnet mask would be used if exactly 4 host bits are available?

255.255.255.240 Topic 11.1.0 - The subnet mask of 255.255.255.224 has 5 host bits. The mask of 255.255.255.128 results in 7 host bits. The mask of 255.255.255.240 has 4 host bits. Finally, 255.255.255.248 represents 3 host bits.

How many usable IP addresses are available on the 192.168.1.0/27 network?

30 Topic 11.1.0 - A /27 mask is the same as 255.255.255.224. This leaves 5 host bits. With 5 host bits, 32 IP addresses are possible, but one address represents the subnet number and one address represents the broadcast address. Thus, 30 addresses can then be used to assign to network devices.

A network administrator subnets the 192.168.10.0/24 network into subnets with /26 masks. How many equal-sized subnets are created?

4 Topic 11.5.0 - The normal mask for 192.168.10.0 is /24. A /26 mask indicates 2 bits have been borrowed for subnetting. With 2 bits, four subnets of equal size could be created.​

If a network device has a mask of /26, how many IP addresses are available for hosts on this network?

62 Topic 11.1.0 - A /26 mask is the same as 255.255.255.192. This leaves 6 host bits. With 6 host bits, 64 IP addresses are possible, but one address represents the subnet number and one address represents the broadcast address. Thus 62 addresses can then be assigned to network hosts.

How many valid host addresses are available on an IPv4 subnet that is configured with a /26 mask?

62 Topic 11.5.0 - When a /26 mask is used, 6 bits are used as host bits. With 6 bits, 64 addresses are possible, but one address is for the subnet number and one address is for a broadcast. This leaves 62 addresses that can be assigned to network devices.

AfriNIC

African Network Info Center; Africa

ARIN

American Registry for Internet Numbers; North America Region

APNIC

Asia Pacific Network Information Centre; Asia/Pacific Region

A typical enterprise network:

Intranet - This is the internal part of a company's network, accessible only within the organization. Devices in the intranet use private IPv4 addresses. DMZ - This is part of the company's network containing resources available to the internet such as a web server. Devices in the DMZ use public IPv4 addresses.

Which organization or group of organizations receives IP addresses from IANA and is responsible for allocating these addresses to ISPs and some organizations?

RIRs

A network address is an address that represents a specific network. A device belongs to this network if it meets three criteria:

It has the same subnet mask as the network address. It has the same network bits as the network address, as indicated by the subnet mask. It is located on the same broadcast domain as other hosts with the same network address.

Which two statements are correct about private IPv4 addresses? (Choose two.)

Private IPv4 addresses are assigned to devices within an organization's intranet (internal network). Any organization (home, school, office, company) can use the 10.0.0.0/8 address.

LACNIC

Regional Latin American and Caribbean IP Addresses Registry; Latin America and some Caribbean Islands

RIPE NCC

Reseaux IP Europeens Network Coordination Centre; Europe, the Middle East Central, and Central Asia

Which statement is true about variable-length subnet masking?

The size of each subnet may be different, depending on requirements. Topic 11.8.0 - In variable-length subnet masking, bits are borrowed to create subnets. Additional bits may be borrowed to create additional subnets within the original subnets. This may continue until there are no bits available to borrow.

Which two situations are the result of excessive broadcast traffic? (Choose two)

slow network operations slow device operations

Why does a Layer 3 device perform the ANDing process on a destination IP address and subnet mask?

to identify the network address of the destination network. Topic 11.1.0 - ANDing allows us to identify the network address from the IP address and the network mask.