100-150 Addressing and Subnet Formats Practice Test 3 — 15 Questions

Question 1

An organization is using Variable Length Subnet Masking (VLSM) to optimize their 10.0.0.0/24 space. They need one subnet for 100 hosts and two subnets for 50 hosts each. Which of the following set of subnets correctly fulfills this requirement without overlapping?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

10.0.0.0/25, 10.0.0.128/26, 10.0.0.192/26. VLSM allows for efficient use of IP space by using different masks for different subnets. To accommodate 100 hosts, a /25 (128 addresses) is needed. To accommodate 50 hosts, /26 subnets (64 addresses) are needed. 10.0.0.0/25 covers 0-127. Then, 10.0.0.128/26 covers 128-191, and 10.0.0.192/26 covers 192-255.

Answer

10.0.0.0/25, 10.0.0.64/26, 10.0.0.128/26

Answer

10.0.0.0/24, 10.0.0.128/26, 10.0.0.192/26

Answer

10.0.0.0/26, 10.0.0.64/26, 10.0.0.128/25

Question 2

Which THREE fields are found in the standard IPv4 header and are directly related to the delivery or identification of the packet across subnets?

Accepted Answer

Source IP Address. The IPv4 header contains several fields essential for routing and delivery. The Source IP Address and Destination IP Address are used by routers to make forwarding decisions. The Time to Live (TTL) field prevents packets from looping infinitely by decrementing at each hop, ensuring the network remains stable during convergence.

Answer

MAC Address

Answer

Sequence Number

Question 3

A host with the IP address 192.168.1.50 and a subnet mask of 255.255.255.0 is attempting to send data to a server at 10.1.1.5. Which address must be configured on the host to allow the data to exit the local subnet?

Accepted Answer

Default Gateway. The host 192.168.1.50/24 and the server 10.1.1.5 are on different subnets, so the host cannot ARP for the server directly. It must forward the frame to its default gateway, which is the router interface on the local subnet that knows how to reach remote networks. Without a default gateway, the host can only communicate with devices in 192.168.1.0/24.

Answer

DNS Server Address

Answer

Loopback Address

Answer

Broadcast Address

Question 4

Refer to the exhibit. Based on the IPv6 configuration of the GigabitEthernet0/0 interface, which statement is true regarding the connectivity of this router?

Accepted Answer

The router can only communicate with other hosts on the local link.. The exhibit shows a GigabitEthernet0/0 interface configured with only a link-local IPv6 address (FE80::/10 range, typically starting with FE80::). A link-local address is automatically generated and is only valid on the local segment; it is never routed beyond the local link. Therefore the router can communicate only with directly connected IPv6 hosts on that link, not with the internet or remote networks.

Answer

The router can communicate with any host on the internet.

Answer

The interface is disabled because it lacks a global address.

Answer

The router will use the FF02::1 address to route external traffic.

Question 5

A network designer is planning to use the 10.50.0.0/16 address space. Which TWO of the following represent valid network IDs for subnets created by further dividing this space into /24 segments?

Accepted Answer

10.50.1.0. Options A (10.50.1.0) and B (10.50.255.0) are correct because when 10.50.0.0/16 is divided into /24 subnets, the third octet becomes the subnet identifier and the fourth octet must be 0, giving valid network IDs such as 10.50.0.0, 10.50.1.0, and 10.50.255.0, all of which fall within the 10.50.0.0–10.50.255.0 range. Option C (10.51.0.0) is outside the 10.50.0.0/16 block, since 10.51.x.x belongs to a different /16. Option D (10.50.0.255) is a host address within 10.50.0.0/24, not a network ID, because the host portion is non-zero. Option E (10.50.1.1) is also a host address in the 10.50.1.0/24 subnet, not a valid network ID.

Answer

10.51.0.0

Answer

10.50.0.255

Answer

10.50.1.1

Question 6

In an IPv6 environment, which address type is automatically configured on every IPv6-enabled interface and is used for neighbor discovery and router solicitation?

Accepted Answer

Link-Local Address. A Link-Local Address (LLA) is automatically configured on every IPv6-enabled interface, even before any router advertisement is received. It is formed using the fe80::/10 prefix and is required for Neighbor Discovery Protocol (NDP) operations including router solicitation, router advertisement, and address resolution.

Answer

Unique Local Address

Answer

Global Unicast Address

Answer

Anycast Address

Question 7

A network engineer is configuring a large subnet for a campus and uses the 172.16.0.0/23 prefix. What is the last usable host address available in this subnet?

Accepted Answer

172.16.1.254. A /23 subnet has 9 host bits (32 - 23 = 9), giving 2^9 - 2 = 510 usable hosts. The subnet 172.16.0.0/23 spans 172.16.0.0 through 172.16.1.255, with the broadcast address at 172.16.1.255 and the last usable host at 172.16.1.254.

Answer

172.16.0.254

Answer

172.16.1.255

Answer

172.16.2.254

Question 8

An engineer needs to subnet a 192.168.10.0/24 network to provide at least 5 usable subnets, with each subnet accommodating a minimum of 25 host devices. Which subnet mask meets these specific design requirements?

Accepted Answer

255.255.255.224. The subnet mask /27 provides 32 total IP addresses per subnet, leaving 30 usable hosts after excluding the network and broadcast addresses. This satisfies the requirement for 25 hosts while yielding 8 total subnets from the original /24 network, easily meeting the minimum threshold of 5 subnets.

Answer

255.255.255.192

Answer

255.255.255.240

Answer

255.255.255.248

Question 9

An administrator needs to subnet the 192.168.10.0/24 network into subnets that can support at least 25 hosts each. Which subnet mask provides the maximum number of subnets while meeting the host requirement?

Accepted Answer

255.255.255.224. To support at least 25 hosts, the subnet must have at least 5 host bits (2^5 - 2 = 30 usable hosts). A /27 mask (255.255.255.224) leaves 5 host bits, providing 30 usable addresses per subnet and yielding 8 subnets from a /24. This maximizes subnet count while still meeting the 25-host requirement.

Answer

255.255.255.248

Answer

255.255.255.240

Answer

255.255.255.192

Question 10

Which IPv6 address type is represented by the prefix fe80::/10?

Accepted Answer

Link-Local. The fe80::/10 prefix is reserved for Link-Local addresses in IPv6. These addresses are automatically configured on all IPv6-enabled interfaces and are essential for neighbor discovery and routing protocol communication on a single local link. Unlike global unicast addresses, these are not routable outside the local segment, making them fundamental for basic connectivity and troubleshooting in IPv6 environments.

Answer

Global Unicast

Answer

Unique Local

Answer

Multicast

Question 11

Which TWO of the following statements correctly describe the characteristics of IPv4 address classes?

Accepted Answer

Class A addresses begin with a binary 0 in the first octet.. Understanding classful boundaries is historical but necessary for identifying legacy network structures and subnetting fundamentals. Class A uses the first octet for network identification with a leading 0, while Class C uses three octets for the network portion with a leading 110. This knowledge assists in recognizing address ranges and identifying potential overlaps in misconfigured legacy network environments.

Answer

Class B addresses use the first 24 bits for the network portion.

Answer

Class D addresses are reserved for private internal usage.

Answer

Class E addresses are used for public internet routing.

Question 12

Refer to the exhibit. An administrator is configuring subnets on a Cisco router. Based on the output, what is the broadcast address for the subnet connected to Gig0/0?

Accepted Answer

172.16.5.15. The interface 172.16.5.1/28 belongs to the subnet starting at 172.16.5.0. Since the /28 mask provides 16 addresses (block size of 16), the range is 172.16.5.0 to 172.16.5.15. The broadcast address is the last address in the subnet, which is 172.16.5.15. Identifying broadcast addresses is essential for troubleshooting traffic propagation and verifying proper segmentation in multi-interface router environments.

Answer

172.16.5.16

Answer

172.16.5.31

Answer

172.16.5.255

Question 13

A network technician is configuring a small branch office network. The ISP has assigned a single public IPv4 address that must be shared by all internal devices. The technician needs a solution that allows multiple internal hosts to communicate on the internet simultaneously without requiring a one-to-one mapping of internal to external addresses. Which technology should the technician implement?

Accepted Answer

Port Address Translation (PAT). Port Address Translation (PAT) is the correct choice because it enables many-to-one translation, allowing multiple internal hosts to share a single public IPv4 address by multiplexing sessions using source port numbers. Dynamic NAT and static NAT both require multiple public addresses or one-to-one mappings, which are not available. Proxy ARP does not perform translation and is irrelevant to internet sharing.

Answer

Static NAT with a one-to-one mapping

Answer

Dynamic NAT with a pool of public addresses

Answer

Proxy ARP

Question 14

A small office technician is assigning IPv4 addresses to devices on a network that will not connect to the internet and uses the 192.168.50.0/24 range. The technician needs to pick an address from the valid host range for this network. Which address should the technician choose?

Accepted Answer

192.168.50.1. For any subnet, the network address and the broadcast address are reserved and cannot be assigned to hosts. In 192.168.50.0/24, the usable host range is 192.168.50.1 through 192.168.50.254, so the only valid host address listed is 192.168.50.1. The address ending in .0 is the network, .255 is the broadcast, and 192.168.51.1 is in a different subnet.

Answer

192.168.50.255

Answer

192.168.50.0

Answer

192.168.51.1

Question 15

A network administrator is documenting the addressing scheme for a new subnet. The subnet uses the IPv4 address 192.168.100.0 with a prefix length of /26. How many usable host addresses are available in this subnet?

Accepted Answer

62. A /26 subnet mask provides 6 host bits, resulting in 2^6 = 64 total addresses. After reserving the network address and the broadcast address, 62 addresses remain for host assignment. This is a fundamental subnetting calculation that every network technician must master.

Answer

126

Answer

30

Answer

64