Network + v2 - 4.3.8 Lesson Review
Which of the following IP address ranges or IP addresses is specifically set aside for use in documentation and examples? 172.16.0.0/12 127.0.0.0 to 127.255.255.255 224.0.0.0 through 239.255.255.255 192.0.2.0/24
Correct Answer: 192.0.2.0/24 Explanation The IP address range 192.0.2.0/24 is specifically reserved for use in documentation and examples. This helps avoid confusion and potential conflicts by ensuring that the examples provided in documentation do not accidentally correspond to real IP addresses in use on the Internet or within private networks. 172.16.0.0/12 is part of the private IP address space intended for use within private networks, not specifically for documentation and examples. 224.0.0.0 through 239.255.255.255 is the IP address range reserved for multicasting, not for documentation and examples. 127.0.0.0 to 127.255.255.255 is reserved for loopback addresses, which are used for internal testing and communication within the host, not for documentation and examples. References 4.3.1 Classful Addressing 4.3.2 Public vs Private Addressing 4.3.3 Other Reserved Address Ranges
Which of the following IP addresses are Class C addresses? (Select two.) 192.15.5.55 125.166.11.0 223.16.5.0 240.0.0.0 189.189.5.2
Correct Answer: 223.16.5.0 Correct Answer: 192.15.5.55 Explanation In this question, the Class C addresses are 192.15.5.55 and 223.16.5.0. The first octet of a Class C address is in the range of 192 to 223. References 4.3.1 Classful Addressing 4.3.2 Public vs Private Addressing 4.3.3 Other Reserved Address Ranges
You're configuring the IP address for a host and have been asked to use the address 192.160.99.110/16. Which subnet mask value would you use? answer 255.0.0.0 255.255.0.0 255.255.252.0 255.255.255.0
Correct Answer: 255.255.0.0 Explanation With CIDR notation, the number of bits in the subnet mask is indicated by the /16 following the IP address. A mask that uses 16 bits is written as 255.255.0.0 in decimal format. Each octet in the mask uses 8 bits, so a mask with 16 bits uses two full octets. Use /8 for the mask 255.0.0.0, and use /24 for the mask 255.255.255.0. In this example, a /24 mask would be the default subnet mask, but the address is using a non-default mask of 255.255.0.0. References 4.3.1 Classful Addressing 4.3.5 Classless Inter-Domain Routing
When subnetting the network address 172.30.0.0/16 to support 12 subnets, what is the new subnet mask in dotted decimal format? 255.255.255.0 255.255.240.0 255.255.0.0 255.255.248.0
Correct Answer: 255.255.240.0 Explanation To support 12 subnets, you round up to the nearest power of 2, which is 16. This requires 4 bits (2^4 = 16). Adding 4 bits to the default /16 mask results in a /20 mask, which in dotted decimal format is 255.255.240.0. 255.255.255.0 represents a /24 mask, which would not provide enough subnets for the requirement. 255.255.248.0 represents a /21 mask, which would provide more subnets than needed and fewer hosts per subnet. 255.255.0.0 is the original /16 mask and does not account for any subnetting. References 4.3.4 IPv4 Address Scheme Design
Why is VLSM considered a complementary technique to supernetting? Because it increases the IPv4 address space Because it allows for the allocation of IP addresses to ISPs Because it simplifies network design Because it allows for more efficient IP address allocation
Correct Answer: Because it allows for more efficient IP address allocation Explanation The correct answer is because it allows for more efficient IP address allocation. VLSM complements supernetting by allowing for more efficient allocation of IP addresses within a network. While supernetting aggregates multiple IP networks into a larger one to simplify routing, VLSM provides the flexibility to allocate IP address ranges to subnets based on actual needs, reducing wastage. VLSM is not specifically about allocating IP addresses to ISPs, but about efficient internal network design. VLSM actually adds complexity to network design due to its flexibility and the need for careful planning. VLSM does not increase the total IPv4 address space. References 4.3.1 Classful Addressing 4.3.6 Variable Length Subnet Masks
How do routers external to the network utilize CIDR? By directly managing the LAN's internal subnet configurations By encrypting data packets based on the CIDR notation By assigning dynamic IP addresses to devices within the network By using the /22 prefix to simplify routing and reduce the complexity of their routing tables
Correct Answer: By using the /22 prefix to simplify routing and reduce the complexity of their routing tables Explanation Routers external to the network use the /22 prefix (or other summarized prefixes provided by CIDR) to simplify routing. This approach allows these routers to treat multiple IP addresses as part of a single, larger network, thereby reducing the number of entries in their routing tables and simplifying the routing process. This is a key advantage of CIDR, as it helps in managing the scalability of Internet routing by reducing the overall complexity. CIDR notation has nothing to do with the encryption of data packets. Encryption is a security measure used to protect data during transmission, and it operates independently of how IP addresses are allocated or summarized. CIDR is concerned with the efficient allocation and management of IP addresses, not with data security. Routers external to the network do not assign dynamic IP addresses to devices within another network. Dynamic IP address assignment is typically handled by DHCP (Dynamic Host Configuration Protocol) servers within the network, not by external routers. CIDR affects how IP addresses are summarized and routed, not how they are assigned to individual devices. Routers external to the network do not manage the LAN's internal subnet configurations. The internal subnetting and IP address management are handled by the network's own administrators and internal routing equipment. External routers use CIDR to simplify the routing to and from the network by recognizing summarized prefixes, but they do not have control over or direct involvement in the network's internal configuration. References 4.3.1 Classful Addressing 4.3.5 Classless Inter-Domain Routing
Consider the following IP addresses: 124.77.8.5 131.11.0.9 190.66.250.10 196.5.89.44 Which of the following represents (in order) the IP address class of each listed IP address? answer Class A, Class B, Class C, Class C Class B, Class B, Class C, Class C Class B, Class B, Class C, Class D Class A, Class B, Class B, Class C Class B, Class C, Class C, Class D
Correct Answer: Class A, Class B, Class B, Class C Explanation The IP addresses listed are of the following classes: Class A, Class B, Class B, Class C. You can identify the IP address class by memorizing the range of values for the first octet. 0-126 = Class A 128-191 = Class B 192-223 = Class C 223-239 = Class D 240-255 = Class E References 4.3.1 Classful Addressing
What is the main advantage of using VLSM over traditional fixed-length subnet masking? It reduces the number of wasted IP addresses. It simplifies the routing table. It allows for the use of the same subnet mask throughout the network. It increases the total number of available IP addresses.
Correct Answer: It reduces the number of wasted IP addresses. Explanation The main advantage of VLSM is its ability to reduce IP address wastage by allowing subnets of different sizes within the same network. This flexibility ensures that each subnet gets just the right amount of IP addresses, minimizing unused addresses. VLSM can actually increase the complexity of the routing table due to the presence of subnets with different masks. VLSM, by definition, allows for different subnet masks to be used within the same network, not the same one. VLSM does not increase the total number of available IP addresses; it just allocates them more efficiently. References 4.3.1 Classful Addressing 4.3.6 Variable Length Subnet Masks
Which process allows hosts using private IP addresses to access the Internet? Network Address Translation (NAT) Dynamic Host Configuration Protocol (DHCP) Internet Protocol Security (IPsec) Domain Name System (DNS)
Correct Answer: Network Address Translation (NAT) Explanation NAT translates private IP addresses to a public IP address for Internet communication, allowing multiple devices on a local network to share a single or a few public IP addresses. This process enables private-addressed hosts to access the Internet. DHCP is used for automatically assigning IP addresses to devices on a network, not for enabling Internet access for private addresses. DNS translates domain names to IP addresses, facilitating user-friendly Internet browsing. It does not enable Internet access for private IP addresses. IPsec is a protocol suite for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet in a data stream. It is not related to enabling Internet access for private addresses. References 4.3.2 Public vs Private Addressing
When performing subnet calculations, what should you remember? (Select two.) Memorize the decimal values for the number of bits set to 1 in an octet within a mask. Always use the same subnet mask for every subnet to simplify calculations. Think in terms of the number of mask bits. The subnet mask can be any random set of numbers as long as it looks complex. Subnet calculations are unnecessary if you use DHCP.
Correct Answer: Think in terms of the number of mask bits. Correct Answer: Memorize the decimal values for the number of bits set to 1 in an octet within a mask. Explanation You should remember the following when performing subnet calculations: Think in terms of the number of mask bits. Thinking in terms of the number of mask bits helps in understanding how subnetting divides the network and determines the size of each subnet. It's a fundamental aspect of subnet calculations. Memorize the decimal values for the number of bits set to 1 in an octet within a mask. Memorizing the decimal values for the number of bits set to 1 in an octet within a mask is crucial for quickly converting between binary and decimal subnet masks, aiding in subnet design and troubleshooting. Using the same subnet mask for every subnet does not allow for flexible network design and can lead to inefficient use of IP addresses. Different subnets may require different sizes based on the number of hosts they support. The subnet mask must follow specific rules and cannot be a random set of numbers. It defines which portion of the IP address represents the network and which part represents hosts within that network. Subnet calculations are essential for designing a network that efficiently uses IP addresses and meets the organization's needs. DHCP is used for assigning IP addresses within those subnets, not for determining the structure of the network itself. References 4.3.4 IPv4 Address Scheme Design
