CISCO CCNA I - Modules 11 - 13 - IP Addressing (Exam Notes)

What is the prefix length notation for the subnet mask 255.255.255.224? a. /26 b. /28 c. /25 d. /27

/27 Explanation: 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.

Match each description with an appropriate IP address. (Not all options are used.) Descriptions: 1. a private address 2. a loopback address 3. an experimental address 4. a TEST-NET address 5. a link-local address IP addresses: 1. 64.102.90.23 2. 169.254.1.5 3. 192.0.2.123 4. 240.2.6.255 5. 172.19.20.5 6. 127.0.0.1

1. a private address (172.19.20.5) 2. a loopback address (127.0.0.1) 3. an experimental address (240.2.6.255) 4. a TEST-NET address (192.0.2.123) 5. a link-local address (169.254.1.5) Explanation: Link-Local addresses are assigned automatically by the OS environment and are located in the block 169.254.0.0/16. The private addresses ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. TEST-NET addresses belong to the range 192.0.2.0/24. The addresses in the block 240.0.0.0 to 255.255.255.254 are reserved as experimental addresses. Loopback addresses belong to the block 127.0.0.0/8.

Refer to the exhibit. IPv6 Address: 2001:DB8:1234:0000::/64 - "Site": Identified by the first zero in :0000::/64. - "Subnet": Represented by the last zero in :0000::/64. - "Sub-site": Indicated by the middle two zeros in :0000::/64. A company is deploying an IPv6 addressing scheme for its network. The company design document indicates that the subnet portion of the IPv6 addresses is used for the new hierarchical network design, with the site subsection to represent multiple geographical sites of the company, the sub-site section to represent multiple campuses at each site, and the subnet section to indicate each network segment separated by routers. With such a scheme, what is the maximum number of subnets achieved per sub-site ? a. 0 b. 4 c. 16 d. 256

16 Explanation: Because only one hexadecimal character is used to represent the subnet, that one character can represent 16 different values 0 through F. In IPv6, each hexadecimal character represents 4 bits. The subnet portion has one hexadecimal character. Since there are 16 possible values in a single hexadecimal character (0 through F), you can have 16 different subnets within each sub-site.

Refer to the exhibit. Router A and Router B are linked. Router A, connected to a switch (172.16.16.0/22), which is connected to PC A Router B, connected to a switch (?), which is connect to PC B. An administrator must send a message to everyone on the router A network. What is the broadcast address for network 172.16.16.0/22? a. 172.16.20.255 b. 172.16.16.255 c. 172.16.19.255 d. 172.16.255.255 e. 172.16.23.255

172.16.19.255 Explanation: The 172.16.16.0/22 network has 22 bits in the network portion and 10 bits in the host portion. Converting the network address to binary yields a subnet mask of 255.255.252.0. The range of addresses in this network will end with the last address available before 172.16.20.0. Valid host addresses for this network range from 172.16.16.1-172.16.19.254, making 172.16.19.255 the broadcast address.

What three blocks of addresses are defined by RFC 1918 for private network use? (Choose three.) a. 192.168.0.0/16 b. 100.64.0.0/14 c. 10.0.0.0/8 d. 239.0.0.0/8 e. 169.254.0.0/16 f. 172.16.0.0/12

192.168.0.0/16 10.0.0.0/8 172.16.0.0/12 (a, c, & f) Explanation: RFC 1918, Address Allocation for Private Internets, defines three blocks of IPv4 address for private networks that should not be routable on the public Internet: - 10.0.0.0/8 - 172.16.0.0/12 - 192.168.0.0/16

Which subnet would include the address 192.168.1.96 as a usable host address? a. 192.168.1.64/26 b. 192.168.1.64/29 c. 192.168.1.32/28 d. 192.168.1.32/27

192.168.1.64/26 Explanation: For the subnet of 192.168.1.64/26, there are 6 bits for host addresses, yielding 64 possible addresses. However, the first and last subnets are the network and broadcast addresses for this subnet. Therefore, the range of host addresses for this subnet is 192.168.1.65 to 192.168.1.126. The other subnets do not contain the address 192.168.1.96 as a valid host address.

Open the PT Activity: Open the command prompt on PC2 and use the "ipv6config" command to note the IPv6 address of PC2. Open the command prompt on PC1 and trace the route to PC2. Perform the tasks in the activity instructions and then answer the question. What are the three IPv6 addresses displayed when the route from PC1 to PC2 is traced? (Choose three.) a. 2001:DB8:1:1::1 b. 2001:DB8:1:1::A c. 2001:DB8:1:2::2 d. 2001:DB8:1:2::1 e. 2001:DB8:1:3::1 f. 2001:DB8:1:3::2 g. 2001:DB8:1:4::1

2001:DB8:1:1::1 2001:DB8:1:2::1 2001:DB8:1:3::2 (a, d, & f) Explanation: Using the "ipv6config" command on PC2 displays the IPv6 address of PC2, which is 2001:DB8:1:4::A. The IPV6 link-local address, FE80::260:70FF:FE34:6930, is not used in route tracing. Using the "tracert 2001:DB8:1:4::A" command on PC1 displays four addresses: 1. 2001:DB8:1:1::1 2. 2001:DB8:1:2::1 3. 2001:DB8:1:3::2 4. 2001:DB8:1:4::A.

Which address prefix range is reserved for IPv4 multicast? a. 224.0.0.0 - 239.255.255.255 b. 169.254.0.0 - 169.254.255.255 c. 240.0.0.0 - 254.255.255.255 d. 127.0.0.0 - 127.255.255.255

224.0.0.0 - 239.255.255.255 Explanation: Multicast IPv4 addresses use the reserved class D address range of 224.0.0.0 to 239.255.255.255.

What is the prefix for the host address 2001:DB8:BC15:A:12AB::1/64? a. 2001:DB8:BC15 b. 2001:DB8:BC15:A c. 2001:DB8:BC15:A:1 d. 2001:DB8:BC15:A:12

2001:DB8:BC15:A Explanation: The network portion, or prefix, of an IPv6 address is identified through the prefix length. A /64 prefix length indicates that the first 64 bits of the IPv6 address is the network portion. Hence the prefix is 2001:DB8:BC15:A.

Which is the compressed format of the IPv6 address 2001:0db8:0000:0000:0ab8:0001:0000:1000? a. 2001:db8:0:1::8:1 b. 2001:db8:1::ab8:0:1 c. 2001:db8::a0b0:8:1 d. 2001:db8::ab8:1:0:1000

2001:db8::ab8:1:0:1000 Explanation: In IPv6, consecutive groups of zeros within an address can be replaced with a double colon (::) once in an address. Additionally, leading zeros within each group can be omitted, but trailing zeros cannot. This compressed format represents the same address while eliminating consecutive zeros and following the rules for leading and trailing zeros.

A site administrator has been told that a particular network at the site must accommodate 126 hosts. Which subnet mask would be used that contains the required number of host bits? a. 255.255.255.240 b. 255.255.255.128 c. 255.255.255.224 d. 255.255.255.0

255.255.255.128 Explanation: 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 of these addresses is the shortest abbreviation for the IP address: 3FFE:1044:0000:0000:00AB:0000:0000:0057? a. 3FFE:1044:0000:0000:00AB::57 b. 3FFE:1044:0:0:AB::57 c. 3FFE:1044::00AB::0057 d. 3FFE:1044::AB::57 e. 3FFE:1044:0:0:00AB::0057 f. 3FFE:1044:0000:0000:00AB::0057

3FFE:1044:0:0:AB::57 Explanation: The rules for reducing the notation of IPv6 addresses are: 1. Omit any leading 0s (zeros) in any hextet. 2. Replace any single, contiguous string of one or more 16-bit hextets consisting of all zeros with a double colon (::). 3. The double colon (::) can only be used once within an address.

What is the usable number of host IP addresses on a network that has a /26 mask? a. 64 b. 62 c. 32 d. 16 e. 254 f. 256

62 Explanation: A /26 mask is the same as 255.255.255.192. The mask leaves 6 host bits. With 6 host bits, 64 IP addresses are possible. One address represents the subnet number and one address represents the broadcast address, which means that 62 addresses can then be used to assign to network devices.

Which three addresses are valid public addresses? (Choose three.) a. 64.104.78.227 b. 172.31.1.25 c. 128.107.12.117 d. 198.133.219.17 e. 192.168.1.245 f. 10.15.250.5

64.104.78.227 128.107.12.117 198.133.219.17 (a, c, & d) Explanation: The ranges of private IPv4 addresses are as follows: - 10.0.0.0 - 10.255.255.255 - 172.16.0.0 - 172.31.255.255 - 192.168.0.0 - 192.168.255.255

A network administrator has received the IPv6 prefix 2001:DB8::/48 for subnetting. Assuming the administrator does not subnet into the interface ID portion of the address space, how many subnets can the administrator create from the /48 prefix? a. 65536 b. 16 c. 256 d. 4096

65536 Explanation: IPv6 addresses are 128 bits long. In this scenario, the network administrator has been allocated a /48 prefix, which means the first 48 bits are dedicated to the network portion. With a network prefix of 48, there will be 16 bits available for subnetting because the interface ID starts at bit 64. Now, IPv6 addresses are typically divided into three parts: - "Network Prefix": The first 48 bits, assigned by the Internet Assigned Numbers Authority (IANA) or a regional Internet registry. - "Subnet ID": The next set of bits used for subnetting. In this case, it's 16 bits (128 - 48(NP) - 64(IID) = 16). - "Interface ID": The last 64 bits, used to identify specific devices within a subnet. Since the administrator is not subnetting into the interface ID (remaining with the default 64 bits for interface IDs), all the subnetting happens within the 16 bits of the subnet ID. Now, to find out how many subnets can be created, you look at the number of bits available for subnetting. The formula to calculate the number of subnets is 2^n, where 'n' is the number of bits available for subnetting. So, 2^16 = 65,536 The conclusion is that the administrator can create 65,536 subnets from the given /48 IPv6 prefix.

Which address is a valid IPv6 link-local unicast address? a. FD80::1:1234 b. FE80::1:4545:6578:ABC1 c. FE0A::100:7788:998F d. FC90:5678:4251:FFFF e. FEC8:1::FFFF

FE80::1:4545:6578:ABC1 Explanation: IPv6 LLAs are in the fe80::/10 range. The /10 indicates that the first 10 bits are fixed and set to "1111:1110:10xx:xxxx". The first hextet (16 bits) of a link-local address must start with "1111:1110:1000:0000" (FE80) and can go up to "1111:1110:1011:1111" (FEBF). The given address "FE80::1:4545:6578:ABC1" follows these rules precisely. The FE80 is in the correct range, and the rest of the address conforms to the expected format. So, "FE80::1:4545:6578:ABC1" is indeed a valid IPv6 link-local unicast address.

Match each IPv4 address to the appropriate address category. (Not all options are used.) Address categories (2 open spots each): 1. Host address 2. Network address 3. Broadcast address IPv4 addresses: 1. 192.168.100.161/25 2. 192.168.1.191/26 3. 10.10.10.128/25 4. 224.10.0.254/24 5. 203.0.113.100/24 6. 172.110.12.64/28 7. 10.0.0.159/27

Host address: 1. 192.168.100.161/25 2. 203.0.113.100/24 Network address: 1. 10.10.10.128/25 2. 172.110.12.64/28 Broadcast address: 1. 192.168.1.191/26 2. 10.0.0.159/27 Explanation: HOST ADDRESSES: "192.168.100.161/25": The address is part of the 192.168.100.128/25 subnet, and it represents a specific device within that subnet. The /25 subnet allows for host addresses ranging from 192.168.100.129 to 192.168.100.254. "203.0.113.100/24": This is a regular host address within the 203.0.113.0/24 subnet, where the last octet can vary from 1 to 254. -------------------- NETWORK ADDRESSES: "10.10.10.128/25": The network address indicates the beginning of the subnet and encompasses all addresses from 10.10.10.128 to 10.10.10.255. It identifies the network itself. "172.110.12.64/28": This represents the network of devices where the range of host addresses is from 172.110.12.65 to 172.110.12.78. The /28 subnet allows for 16 host addresses. -------------------- BROADCAST ADDRESSES: "192.168.1.191/26": In a subnet with a /26 mask, the broadcast address is the last address in the range. Here, it's 192.168.1.191, signifying the end of the subnet. "10.0.0.159/27": With a /27 subnet, the broadcast address is the last address within the subnet range (10.0.0.159 in this case), marking the end for broadcast purposes.

Which protocol supports Stateless Address Autoconfiguration (SLAAC) for dynamic assignment of IPv6 addresses to a host? a. DHCPv6 b. ARPv6 c. ICMPv6 d. UDP

ICMPv6 Explanation: SLAAC uses ICMPv6 messages when dynamically assigning an IPv6 address to a host. DHCPv6 is an alternate method of assigning an IPv6 addresses to a host. ARPv6 does not exist. Neighbor Discovery Protocol (NDP) provides the functionality of ARP for IPv6 networks. UDP is the transport layer protocol used by DHCPv6.

Refer to the exhibit. Network A - 100 Hosts Network B - 50 Network C - 25 Hosts Network D - 2 Hosts (Link between routers) Match the network with the correct IP address and prefix that will satisfy the usable host addressing requirements for each network. IP addresses: 1. 192.168.0.96 /27 2. 192.168.0.128 /25 3. 192.168.0.0 /26 4. 192.168.0.80/30

Network A (192.168.0.128 /25) Network B (192.168.0.0 /26) Network C (192.168.0.96 /27) Network D (192.168.0.80/30) Explanation: Network A needs to use 192.168.0.128 /25, which yields 128 host addresses. Network B needs to use 192.168.0.0 /26, which yields 64 host addresses. Network C needs to use 192.168.0.96 /27, which yields 32 host addresses. Network D needs to use 192.168.0.80/30, which yields 4 host addresses.

Which service provides dynamic global IPv6 addressing to end devices without using a server that keeps a record of available IPv6 addresses? a. SLAAC b. static IPv6 addressing c. stateless DHCPv6 d. stateful DHCPv6

SLAAC Explanation: Using stateless address autoconfiguration (SLAAC), a PC can solicit a router and receive the prefix length of the network. From this information the PC can then create its own IPv6 global unicast address.

Three methods allow IPv6 and IPv4 to co-exist. Match each method with its description. (Not all options are used.) Descriptions: 1. The IPv4 packets and IPv6 packets coexist in the same network. 2. The IPv6 packet is transported inside an IPv4 packet. 3. IPv6 packets are converted into IPv4 packets, and vice versa. Methods: 1. DHCP 2. Translation 3. Tunneling 4. Dual-stack

The IPv4 packets and IPv6 packets coexist in the same network. (Dual-stack) The IPv6 packet is transported inside an IPv4 packet. (Tunneling) IPv6 packets are converted into IPv4 packets, and vice versa. (Translation) Explanation: "Dual-stack": This method involves running both IPv4 and IPv6 on network devices simultaneously. It allows for a gradual transition and coexistence of both protocols during the migration from IPv4 to IPv6. "Tunneling": In tunneling, IPv6 packets are encapsulated within IPv4 packets, facilitating the transport of IPv6 traffic over an IPv4 infrastructure. This is often used in scenarios where an organization wants to gradually adopt IPv6 without an immediate overhaul of their existing IPv4 network. "Translation": Translation involves converting IPv6 packets to IPv4 packets (or vice versa) to enable communication between networks using different IP versions. This is useful when there is a need for communication between IPv4 and IPv6 networks, and direct native communication isn't possible.

A host is transmitting a multicast. Which host or hosts will receive it? a. a specially defined group of hosts b. one specific host c. the closest neighbor on the same network d. all hosts with the same IP address

a specially defined group of hosts Explanation: Multicast communication involves sending data to a specific group of hosts known as a multicast group. Each host interested in receiving the data joins this predefined group. The option, "a specially defined group of hosts," is correct because multicast enables efficient one-to-many communication to a chosen set of receivers, making it distinct from unicast, broadcast, or communication to the closest neighbor.

An IPv6 enabled device sends a data packet with the destination address of FF02::1. What is the target of this packet?​ a. all IPv6 enabled devices on the local link​ or network b. the one IPv6 device on the link that has been uniquely configured with this address c. only IPv6 DHCP servers​ d. only IPv6 configured routers

all IPv6 enabled devices on the local link​ or network Explanation: This address is one of the assigned IPv6 multicast addresses. FF02::1 is the "all-nodes multicast group, " which means that packets addressed to FF02::1 are for all IPv6 enabled devices on the link or network. A packet sent to this group is received and processed by all IPv6 interfaces on the link or network. FF02::2 is referred to as the "all-routers multicast group" and is for all IPv6 routers that exist on the network. A packet sent to this group is received and processed by all IPv6 routers on the link or network.

Which type of IPv6 address refers to any unicast address that is assigned to multiple hosts? a. unique local b. anycast c. global unicast d. Link-local

anycast Explanation: The IPv6 specifications include anycast addresses. An "anycast address" is any unicast IPv6 address that is assigned to multiple devices.

A message is sent to all hosts on a remote network. Which type of message is it? a. unicast b. multicast c. directed broadcast d. limited broadcast

directed broadcast Explanation: A directed broadcast is a message sent to all hosts on a specific network. It is useful for sending a broadcast to all hosts on a nonlocal network. A multicast message is a message sent to a selected group of hosts that are part of a subscribing multicast group. A limited broadcast is used for a communication that is limited to the hosts on the local network. A unicast message is a message sent from one host to another.

A user issues a ping 192.135.250.103 command and receives a response that includes a code of 1. What does this code represent? a. network unreachable b. protocol unreachable c. host unreachable d. port unreachable

host unreachable Explanation: When a user issues a 'ping' command and receives a response code of 1, it indicates that the destination host is unreachable. This code is generated when the network cannot deliver the ICMP (Internet Control Message Protocol) Echo Request to the specified host. It could be due to issues such as the host being down, unreachable, or there's a network problem preventing the communication with the destination host. Other codes: - 0 : "Echo Reply (Ping Reply)": Indicates that the destination host is reachable and has successfully received the ICMP Echo Request. - 1 : "Host Unreachable": The network is reachable, but the specified host is not reachable. This could be due to the host being down, unreachable, or other network issues. - 2 : "Protocol Unreachable": The network is reachable, but the designated transport protocol is not supported or active on the destination host. - 3 : "Port Unreachable": The network and host are reachable, but the specified port on the destination host is not open or available. - 4 : "Fragmentation Needed and Don't Fragment (DF) Set": The packet needs to be fragmented for transmission, but the Don't Fragment (DF) flag is set, and fragmentation is not allowed. - 5 : "Source Route Failed": The source route specified in the packet is incorrect or not accepted by one of the routers along the path. - 8 : "Echo Request (Ping Request)": This is a request for an Echo Reply and is commonly used in ping commands to test network connectivity. These codes are part of the ICMP protocol and help diagnose network issues by providing information about the status of the communication between the source and destination hosts.

What type of IPv6 address is FE80::1? a. link-local b. global unicast c. loopback d. multicast

link-local Explanation: Link-local IPv6 addresses start with FE80::/10, which is any address from FE80:: to FEBF::. Link-local addresses are used extensively in IPv6 and allow directly connected devices to communicate with each other on the link they share.

An administrator wants to create four subnetworks from the network address 192.168.1.0/24. What is the network address and subnet mask of the second usable subnet? a. subnetwork 192.168.1.32 & subnet mask 255.255.255.240 b. subnetwork 192.168.1.128 & subnet mask 255.255.255.192 c. subnetwork 192.168.1.64 & subnet mask 255.255.255.192 d. subnetwork 192.168.1.8 & subnet mask 255.255.255.224 e. subnetwork 192.168.1.64 & subnet mask 255.255.255.240

subnetwork 192.168.1.64 & subnet mask 255.255.255.192 Explanation: The number of bits that are borrowed would be two, thus giving a total of 4 useable subnets: - 192.168.1.0 - 192.168.1.64 - 192.168.1.128 - 192.168.1.192 Because 2 bits are borrowed, the new subnet mask would be /26 or 255.255.255.192

What is used in the EUI-64 process to create an IPv6 interface ID on an IPv6 enabled interface? a. the MAC address of the IPv6 enabled interface b. an IPv4 address that is configured on the interface c. a randomly generated 64-bit hexadecimal address d. an IPv6 address that is provided by a DHCPv6 server

the MAC address of the IPv6 enabled interface Explanation: The EUI-64 process uses the MAC address of an interface to construct an interface ID (IID). Because the MAC address is only 48 bits in length, 16 additional bits (FF:FE) must be added to the MAC address to create the full 64-bit interface ID.

How many bits must be borrowed from the host portion of an address to accommodate a router with five connected networks? a. three b. five c. two d. four

three Explanation: Each network that is directly connected to an interface on a router requires its own subnet. The formula 2^n, where n is the number of bits borrowed, is used to calculate the available number of subnets when borrowing a specific number of bits.

Which ICMPv6 message is sent when the IPv6 hop limit field of a packet is decremented to zero and the packet cannot be forwarded? a. port unreachable b. time exceeded c. network unreachable d. protocol unreachable

time exceeded Explanation: ICMPv6 uses the hop limit field in the IPv6 packet header to determine if the packet has expired. If the hop limit field has reached zero, a router will send a time exceeded message back towards the source indicating that the router cannot forward the packet.

What is the purpose of ICMP messages? a. to ensure the delivery of an IP packet b. to inform routers about network topology changes c. to monitor the process of a domain name to IP address resolution d. to provide feedback of IP packet transmissions

to provide feedback of IP packet transmissions Explanation: The purpose of ICMP messages is to provide feedback about issues that are related to the processing of IP packets.

A user executes a traceroute over IPv6. At what point would a router in the path to the destination device drop the packet? a. when the value of the Hop Limit field reaches 255 b. when the target host responds with an ICMP echo reply message c. when the router receives an ICMP time exceeded message d. when the value of the Hop Limit field reaches zero

when the value of the Hop Limit field reaches zero Explanation: When a traceroute is performed, the value in the Hop Limit field of an IPv6 packet determines how many router hops the packet can travel. Once the Hop Limit field reaches a value of zero, it can no longer be forwarded and the receiving router will drop the packet.