CCNA Practice Certification Exam # 1

A WLAN (Wireless Local Area Network) is a better solution than a LAN (Local Area Network) when user mobility is needed. Unlike a LAN, which requires wired connections, a WLAN allows users to connect to the network wirelessly, enabling them to move freely within the network coverage area. This is particularly beneficial in environments where users need to access the network while on the move, such as in a large office space or a public area. WLANs provide flexibility and convenience for users, making them a better solution when user mobility is a requirement.

The correct answer is "passive-interface serial 0/0/0". This command will configure the serial interface 0/0/0 on router B as a passive interface for RIP. A passive interface does not send or receive routing updates. Therefore, by configuring the serial interface as passive, router B will not send routing updates to router A.

In Network Address Translation (NAT) overloading, multiple private IP addresses are mapped to one public IP address. This allows multiple devices with private IP addresses to share a single public IP address when communicating with external networks. This process is commonly used in home and small office networks where there are more devices than available public IP addresses. By mapping multiple private IP addresses to one public IP address, NAT overloading helps conserve the limited number of available public IP addresses.

In order to delete or add VLANs to a management domain on a Catalyst switch, it must be in the "server" mode. In this mode, the switch can create, modify, and delete VLANs and propagate these changes to other switches in the VTP domain. The "client" mode can only receive and synchronize VLAN information from the server, while the "transparent" mode does not participate in VTP updates. The "domain" and "designated" options are not valid VTP modes.

The Spanning Tree Protocol creates a loop-free path through a switch network. It does this by identifying and disabling redundant links in the network, ensuring that there is only one active path between any two switches. This prevents the formation of loops, which can cause network congestion and broadcast storms. By using a tree-like structure, the Spanning Tree Protocol allows for efficient and reliable communication within the network.

Host A will send ARP requests to hosts C, D, and F because they are connected to the same VLAN as Host A. Host B, E, and G are not on the same VLAN as Host A, so they will not receive ARP requests from Host A.

The purpose of the Spanning Tree Protocol (STP) is to prevent Layer 2 loops. Layer 2 loops can occur in a network when there are redundant links between switches, causing broadcast storms and network congestion. STP helps to eliminate these loops by selecting a single, optimal path for data transmission and blocking the redundant paths. This ensures that there is a loop-free topology in the network, improving its stability and performance.

The problem is most likely that interfaces FA0/1 on SW_1 and SW_2 need to be configured as trunk ports. Trunk ports are used to carry traffic for multiple VLANs, while access ports are used for individual VLANs. Since workstations in VLAN 20 cannot ping workstations in VLAN 20 on the opposite switch, it suggests that the VLAN traffic is not being properly carried between the switches. By configuring FA0/1 on both switches as trunk ports, the VLAN traffic will be able to pass between the switches, allowing workstations in VLAN 20 to communicate with each other.

The correct answer is "RT_1(config-subif)# encapsulation dot1q 10". This command is used to configure the VLAN encapsulation on the router interface Fa 0/1. The "dot1q" keyword indicates that the VLAN encapsulation will be using the IEEE 802.1Q standard, and the "10" specifies the VLAN ID that will be associated with this interface.

The IP address 172.16.134.48/27 is a usable host address. The "/27" indicates that the first 27 bits of the IP address are the network portion, leaving the remaining 5 bits for host addresses. This means that there are 32 possible host addresses in this network. The given IP address falls within this range and can be assigned to a device on the network as a usable host address.

The route that will appear in the routing table for the network 192.168.168.0 is the "S" route. This is because the "S" route has the lowest administrative distance of 1, indicating that it is a static route. The other routes have higher administrative distances, indicating that they are learned through dynamic routing processes.

The error message "No password set" indicates that a password has not been set for the console port. This means that anyone can access the router's console without authentication, which is a security risk. To resolve this issue, the network administrator should use the password command to set a password for the console port.

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In an access control list, the "host" keyword can be used to replace a wildcard mask or address and wildcard mask pair. This keyword is used to specify a single host or IP address. The "any" keyword can also be used to replace a wildcard mask or address and wildcard mask pair. This keyword is used to match any IP address or host. Both keywords provide flexibility in specifying access control rules without the need for specific addresses or masks.

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HDLC (High-Level Data Link Control) is the default Layer 2 encapsulation protocol for a synchronous serial interface on a Cisco router. HDLC is a bit-oriented protocol that provides both connection-oriented and connectionless service options. It is widely used in Cisco networks and is the default encapsulation protocol for synchronous serial interfaces unless otherwise specified. HDLC provides reliable and efficient data transmission over synchronous serial links, making it a suitable choice for Cisco routers.

The most likely cause of the problem is the data link layer. The data link layer is responsible for the reliable transmission of data between network devices over a physical link. If the routers cannot ping from serial interface to serial interface, it suggests that there may be an issue with the data link layer, such as a problem with the physical connection or with the data link protocols being used.

The router OSPF process uses the IP address of the loopback interface to assign the router ID. The loopback interface is a virtual interface that is always up and available, even if the physical interfaces are down. Assigning the router ID based on the loopback interface IP address ensures that the router ID remains stable and does not change even if there are changes in the physical interfaces or their IP addresses.

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Based on the given configuration, HDLC will be used for Layer 2 encapsulation for connection D. The configuration does not mention any specific encapsulation protocol, so the default protocol, which is HDLC, will be used.

RSTP (Rapid Spanning Tree Protocol) was developed to decrease the time needed for switch ports to move to the forwarding state in a redundantly switched topology. It improves the convergence time of the spanning tree protocol by reducing the time it takes for a switch to transition from the blocking state to the forwarding state. This helps to minimize network downtime and improve network performance in environments with redundant links.

The correct answer is "RouterA(config)# router ospf 1" because this command is used to enable OSPF routing process on the router.

The correct answer is "RouterA(config-router)# network 192.168.2.0 0.0.0.255 area 0" because this command is used to advertise the network 192.168.2.0 with a wildcard mask of 0.0.0.255 into OSPF area 0. This command tells the router to include this network in its OSPF routing table and advertise it to other OSPF routers in the same area.

The network has three broadcast domains because each VLAN represents a separate broadcast domain. The Production VLAN on switch fl-1 and the Development VLAN on switch fl-2 are two separate broadcast domains, and the third broadcast domain is the default VLAN that exists on both switches.

The network has nine collision domains because each port on a switch represents a separate collision domain. There are a total of nine ports on both switches, so there are nine collision domains in the network.

The type of header shown in the exhibit is IPv6.

The error message indicates that the switch SwA received an 802.1Q BPDU on a non-trunk port, specifically FastEthernet0/1 VLAN1. This suggests that the port on SwA is configured as a trunk port, capable of carrying multiple VLANs, while the port on SwB is configured as an access port, only allowing traffic from a single VLAN. This inconsistency in port configuration is causing the error message to be generated.

SW3 will become the root bridge because it has the lowest bridge ID. SW4 will get a port blocked because it has the second highest bridge ID among the switches.

The EIGRP DUAL algorithm uses the topology table to calculate the best route to each destination router. The topology table contains information about all the routers in the network and their respective routes. This table is constantly updated with the latest information about network topology changes. The DUAL algorithm uses this information to determine the best path to each destination based on metrics such as bandwidth, delay, reliability, and load. The routing table, on the other hand, is the table that contains the actual routes that will be used for forwarding packets.

The VLAN 99 is missing because it has not been manually entered into the VLAN database using the "vlan 99" command. This command is necessary to create and activate VLAN 99 on the switch. Without this command, VLAN 99 will not be recognized or available for use.

The correct answer is "router ospf 1". This command is used to configure OSPF on router A with process ID 1. The other commands mentioned in the exhibit are either duplicates or incorrect, as they repeat the same command or use incorrect process IDs.

Extended access control lists (ACLs) are used to filter network traffic based on specific criteria. By placing the ACLs as close as possible to the source of the traffic to be denied, network administrators can prevent unnecessary traffic from entering the network, thus improving overall network performance and reducing the load on other network devices. This placement allows for more efficient filtering and reduces the potential for unwanted traffic to consume network resources.

When four bits are borrowed to create subnets, it means that the subnet mask has been increased by four bits, resulting in a subnet mask of 255.255.255.240. This means that the last four bits of the IP address are used for subnetting. The three addresses that have subnet addresses are the ones where the last four bits are not all zeros or all ones. In this case, the subnet addresses are 192.168.14.16, 192.168.14.32, and 192.168.14.208.

802.11g is the correct answer because it is the wireless standard that works only in the 2.4 GHz range and provides speeds up to 54 Mb/s. This standard was introduced as an improvement over the 802.11b standard, offering faster speeds while still operating in the same frequency range. It is backward compatible with 802.11b devices, making it a popular choice for home and small office networks.

TCP (Transmission Control Protocol) is a reliable transport protocol that ensures data transport reliability by providing mechanisms for error detection, retransmission of lost packets, and flow control. It also establishes, maintains, and terminates virtual circuits between communicating devices, ensuring a reliable and ordered delivery of data. Therefore, the two characteristics of TCP mentioned in the answer are data transport reliability and establishing, maintaining, and terminating virtual circuits.

The output suggests that the management VLAN for the switch is VLAN 99.

The three factors that contribute to congestion on an Ethernet LAN are improper placement of enterprise level servers, addition of hosts to a physical segment, and increasing use of bandwidth intensive network applications. Improper placement of servers can lead to congestion as it may result in uneven distribution of network traffic. Adding more hosts to a physical segment without considering the capacity can also cause congestion. Similarly, the use of bandwidth intensive applications can consume a significant amount of network resources, leading to congestion.

The first explanation for this problem is that a router is required for communication between VLANs. VLANs are designed to separate broadcast domains, and without a router to connect them, communication between VLANs is not possible.
The second explanation is that the hosts are in separate broadcast domains. This is a characteristic of VLANs - they create separate broadcast domains, which means that broadcasts sent by hosts in one VLAN will not be received by hosts in another VLAN.

The correct answer states that PDU #1 is a frame, PDU #3 is a segment, and the order in which these PDUs are created during the encapsulation process is 3, 4, 1, 2. This means that PDU #1 is created after PDU #4, which is a transport layer PDU, and PDU #3, which is a segment. The order of creation suggests that the encapsulation process starts at the transport layer, then moves to the network layer (PDU #3), followed by the data link layer (PDU #1), and finally the application layer (PDU #2 is not mentioned in the answer).

The most likely problem is that the IP address of computer A is incorrect. This is because if the IP address is incorrect, it will not be able to communicate with other devices on the network, such as RT_1. The other options mentioned in the question do not directly relate to the issue of computer A being unable to ping RT_1.

The most likely problem is that R1 or R2 does not have a network statement for the 172.16.100.0 network. This is indicated by the fact that when the "show ip ospf neighbor" command is given, no output is shown. OSPF neighbors are formed based on the network statements configured on the routers, and if the network statement for the 172.16.100.0 network is missing, OSPF neighbors will not be established. However, the "show ip interface brief" command shows that all interfaces are up and up, indicating that the physical connections are functioning properly.

The appropriate route for the ISP to configure for the XYZ network would be "ISP# ip route 192.135.250.0 255.255.255.248 s0/0/1". This is because it specifies the correct destination network (192.135.250.0) and subnet mask (255.255.255.248) for the XYZ network, and it specifies the correct outgoing interface (s0/0/1) for forwarding the traffic to the XYZ network.

When creating a standard access control list, two pieces of information are required. The first is the source address and wildcard mask, which determine the specific source IP addresses that will be affected by the access control list. The second is the access list number between 1 and 99, which identifies the access control list itself and allows it to be referenced and applied to the appropriate interfaces or traffic.

The given answer is correct because it includes three subnet masks that can accommodate the specified number of hosts for each network.

- Network 1 requires a subnet mask that can accommodate 500 hosts, so the subnet mask 255.255.254.0 is suitable as it allows for 512 hosts.
- Network 2 requires a subnet mask that can accommodate 100 hosts, so the subnet mask 255.255.252.0 is suitable as it allows for 1024 hosts.
- Network 3 requires a subnet mask that can accommodate 1000 hosts, so the subnet mask 255.255.255.128 is suitable as it allows for 1022 hosts.

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Distance vector routing protocols, such as RIP (Routing Information Protocol), operate by sending their routing tables to directly connected neighbors. This means that each router shares information about the networks it knows how to reach with its immediate neighbors. By exchanging this information, routers can build a picture of the entire network and determine the best path to reach each network. The hop count, or the number of routers a packet must pass through, is one of the metrics used by distance vector protocols to determine the best path. However, it is not the only metric, as other factors like link speed or network congestion may also be considered.

A concentrator is a network device commonly used to allow multiple VPN connections into a corporate network. It acts as a central point for managing and processing VPN connections, allowing remote users to securely connect to the corporate network over the internet. By using a concentrator, multiple VPN tunnels can be established simultaneously, providing secure access to the corporate network for remote employees, branch offices, or business partners. This helps to ensure data confidentiality, integrity, and privacy while enabling remote access to network resources.

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Two possible causes for the problem could be that the Ethernet1 interface of the Popcorn router is shutdown and that the Popcorn router did not include network 192.168.12.0 in its routing configuration. This means that the administrator is unable to ping the Ethernet1 interface because it is not operational, and the Popcorn router is not aware of the network 192.168.12.0, so it cannot forward any traffic to that network.

The debug output shows that the router is attempting to send the frame-relay packet to the IP address 192.168.11.2, which is its own IP address. This indicates that there is an incorrect IP address in the map statement. The map statement should specify the IP address of the destination router, in this case, R1. Since the IP address is incorrect, the packet is not being sent to the correct destination, resulting in the unsuccessful ping.

The three examples of TCP/IP application layer protocols are:
1. A terminal emulation protocol that supports remote console connections with various network devices. This protocol allows users to access and control network devices remotely as if they were directly connected to them.
2. A protocol responsible for transporting electronic mail on TCP/IP networks and the Internet. This protocol is used for sending and receiving emails over the network.
3. A protocol that exchanges network management information between a network device and a management console. This protocol is used for monitoring and managing network devices, allowing administrators to configure and troubleshoot them.