CCNA Certification Practice #3

The "passive-interface serial 0/0/0" command can be used on router B to prevent RIP from sending updates to router A. This command puts the specified interface into passive mode, which means that it will not send any routing updates. In this case, by using the command on the serial 0/0/0 interface, router B will stop sending RIP updates to router A.

In order to delete or add VLANs to a management domain in a Catalyst switch, it must be in the "server" VTP mode. The server mode allows the switch to create, modify, and delete VLAN information and propagate it to other switches in the same VTP domain. By being in server mode, the switch can actively participate in the VTP domain and make changes to the VLAN configuration.

NAT overloading, also known as Port Address Translation (PAT), is a process in which multiple private IP addresses are mapped to one public IP address. This allows multiple devices within a private network to share a single public IP address when communicating with devices on the internet. The router keeps track of the source port numbers to differentiate between the different private IP addresses. This technique helps conserve the limited pool of public IP addresses and provides a level of security by hiding the internal IP addresses from external networks.

The route that will appear in the routing table for network 192.168.168.0 is "S 192.168.168.0/24 [1/0] via 192.168.200.1". This is because the "S" indicates that the route was learned through a static routing process, and it has the lowest administrative distance of 1. The other routes have higher administrative distances, indicating that they were learned through dynamic routing processes.

To configure a router to route within OSPF area 0, two commands are required. The first command is "RouterA(config)# router ospf 1" which enables OSPF routing process with an OSPF process ID of 1. The second command is "RouterA(config-router)# network 192.168.2.0 0.0.0.255 area 0" which specifies the network address and subnet mask to be included in OSPF routing and assigns it to area 0. These two commands together enable OSPF routing and add the specified network to area 0 for routing.

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 identifies and blocks redundant paths in the network, allowing for a single active path while keeping the other paths in a standby mode. This ensures that there is no looping of Ethernet frames, maintaining network stability and preventing disruptions.

The keywords "host" and "any" can be used in an access control list to replace a wildcard mask or address and wildcard mask pair. The keyword "host" is used to specify a single host or IP address, while the keyword "any" is used to represent all IP addresses or any source/destination. These keywords provide flexibility in defining access control rules by allowing specific or generic addressing options.

A WLAN (Wireless Local Area Network) is a better solution than a LAN (Local Area Network) when user mobility is needed. WLAN allows users to connect to the network and access resources without being physically connected through cables, providing flexibility and freedom of movement. This is particularly advantageous in environments where users need to move around and stay connected to the network at the same time, such as in large office spaces, airports, or public places. By using WLAN, users can maintain connectivity and access network resources from different locations within the coverage area.

Host A will send ARP requests to hosts C, D, and F because they are connected to the same VLAN as host A. When host A needs to communicate with hosts on the same VLAN, it sends out an ARP request to discover their MAC addresses. Hosts B, E, and G are not on the same VLAN as host A, so they will not receive ARP requests from host A.

Spanning Tree Protocol (STP) creates a loop-free path through a switch network. It is a network protocol that prevents loops in Ethernet networks by selectively blocking certain redundant links. STP calculates the shortest path to the root bridge and disables all other paths, ensuring that there is only one active path between any two network devices. This prevents broadcast storms and ensures a stable and efficient network topology.

When creating a standard access control list, two pieces of information are required. The first is the source address and wildcard mask, which specify the source of the traffic that will be filtered by the access control list. The second is the access list number between 1 and 99, which is used to identify and apply the access control list to an interface or a specific traffic flow. These two pieces of information are necessary to properly configure and implement a standard access control list.

The OSPF process on the router assigns the router ID based on the IP address of the loopback interface. The loopback interface is a logical interface that is always up and reachable, making it a stable and reliable choice for the router ID. The IP address of the loopback interface is typically chosen to be a unique and static address, ensuring consistency in the router ID across reboots or interface changes.

Ports listen and learn before going into the forwarding state is a true statement regarding the states of the IEEE 802.1D Spanning Tree Protocol. In the Spanning Tree Protocol, ports initially start in the blocking state, where they do not forward any traffic. They then transition to the listening state, where they start to receive and process BPDUs (Bridge Protocol Data Units) to determine the network topology. After that, they enter the learning state, where they populate their MAC address tables. Finally, they move to the forwarding state, where they actively forward data packets.

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 "encapsulation dot1q" command is used to specify the VLAN encapsulation method, and the "10" parameter specifies the VLAN ID.

RSTP (Rapid Spanning Tree Protocol) is an industry-wide specification developed to decrease the time required for switch ports operating in a redundantly switched topology to transition to the forwarding state. RSTP improves the convergence time of the Spanning Tree Protocol (STP) by reducing the amount of time it takes for a switch port to transition from the blocking state to the forwarding state. This allows for faster network convergence and improved network performance in redundant switch topologies.

The correct answer is 802.11g. This wireless standard operates in the 2.4 GHz frequency range and can provide speeds of up to 54 Mb/s. It is an improvement over the previous 802.11b standard, offering faster data transfer rates.

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. It is widely used in synchronous serial communication and is the default encapsulation protocol for Cisco routers. HDLC is simple, efficient, and reliable, making it suitable for various network environments.

The IP address 172.16.134.48/27 is a usable host address because it falls within the range of IP addresses that can be assigned to devices on a network. The "/27" indicates that the first 27 bits of the IP address are used to identify the network, leaving 5 bits for host addresses. Since the host address in this case is 48, it falls within the range of usable host addresses on the network.

The error message in the exhibit suggests that there is an issue with the password command for the console port. This means that the password for accessing the console port has not been set. As a result, the router is unable to proceed with the initial configuration. To resolve this problem, the network administrator needs to set a password for the console port using the password command.

The EIGRP DUAL algorithm uses the topology table to calculate the best route to each destination router. The topology table contains information about the network topology, including the metrics and costs associated with each route. By analyzing this information, the algorithm determines the most efficient path to reach each destination router.

The network consists of two switches, fl-1 and fl-2, each with all ports in a separate VLAN. Each VLAN represents a separate broadcast domain, so there are three broadcast domains in total. Since each switch is considered a separate collision domain, and there are three switches in total, there are nine collision domains in the network.

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The debug output shows that the frame-relay packet is being sent to the IP address 192.168.11.1, which is the IP address of R1. However, in the frame-relay map statement, the IP address specified is 192.168.11.2, which is the IP address of R3 itself. Therefore, the problem is that there is an incorrect IP address in the map statement.

Extended access control lists (ACLs) should be placed as close as possible to the source of the traffic to be denied. This is because ACLs are used to filter network traffic based on specific criteria, such as source and destination IP addresses, protocol types, and port numbers. By placing the ACLs closer to the source of the traffic, they can be applied earlier in the network path, allowing for more efficient and effective filtering. This helps to reduce unnecessary network traffic and potential security risks.

The access list should be applied to the interface that connects to the Records Server. In this case, it is the interface fa0/0 on the Athena device.

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The error message indicates that a BPDU (Bridge Protocol Data Unit) was received on a non-trunk port (FastEthernet0/1) in VLAN1. This suggests that the SwA port is configured as a trunk port, which is expected to receive BPDU messages, while the SwB port is configured as an access port, which should not be receiving BPDU messages. This inconsistency in port configuration is causing the error message to be generated.

The first explanation for this problem is that a router is required for communication between VLANs. VLANs are logically separate networks, 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. Each VLAN has its own broadcast domain, and hosts within a VLAN can communicate with each other using broadcast messages. However, hosts in one VLAN cannot directly communicate with hosts in another VLAN using broadcast messages.

TCP (Transmission Control Protocol) is a reliable transport protocol that ensures data transport reliability by providing error detection, retransmission of lost packets, and flow control mechanisms. 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 are data transport reliability and establishing, maintaining, and terminating virtual circuits.

The correct answer is "ISP# ip route 192.135.250.0 255.255.255.248 s0/0/1". This is the appropriate route for the ISP to configure for the XYZ network because it specifies the destination network 192.135.250.0 with a subnet mask of 255.255.255.248, which indicates a /29 subnet. This route is configured on the s0/0/1 interface, which is the interface connected to the XYZ network. This route will allow the ISP to forward traffic destined for the XYZ network to the correct interface.

Two possible causes for the problem could be that the Ethernet1 interface of the Popcorn router is shutdown or that the Popcorn router did not include network 192.168.12.0 in its routing configuration.

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. This suggests that OSPF neighbors have not been established, which can occur if the network statement is missing for the specific network.

SW3 will become the root bridge because it has the lowest bridge ID. SW4 will have a port blocked because it is not the root bridge and it has the highest bridge ID among the remaining switches.

Split horizon and hold-down timers are two measures used to prevent routing loops in networks that use distance vector routing protocols. Split horizon is a technique where a router does not advertise routes back out of the interface from which it learned them, preventing loops from occurring. Hold-down timers are used to temporarily ignore route updates after a route has been invalidated, allowing time for the network to stabilize and prevent incorrect route information from being propagated. These measures help to ensure the stability and efficiency of the network's routing system.

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 access the corporate network. The concentrator authenticates and encrypts the incoming VPN connections, ensuring the confidentiality and integrity of the data transmitted between the remote users and the corporate network. By using a concentrator, the corporate network can efficiently handle multiple VPN connections from different remote locations.

The most likely cause of the problem is the data link layer. The data link layer is responsible for the physical transmission of data between network devices, such as routers. If the routers are unable to ping from serial interface to serial interface, it suggests that there may be an issue with the data link layer, such as a faulty cable or misconfigured network interface cards.

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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 bottlenecks and congestion if they are not strategically positioned. Adding more hosts to a physical segment can increase the traffic and cause congestion. Similarly, as the use of bandwidth intensive network applications increases, it can consume more network resources and lead to congestion.

Based on the given configuration, HDLC (High-Level Data Link Control) will be used for Layer 2 encapsulation for connection D. This is because the "no shutdown" command enables the interface, and HDLC is the default encapsulation on Cisco routers unless otherwise specified.

From the given output, we can conclude that the management VLAN is VLAN 99.

When four bits are borrowed to create subnets, the subnet mask becomes 255.255.255.240. This means that the subnet addresses will have the last four bits of the host portion set to 0. Looking at the given addresses, 192.168.14.16, 192.168.14.32, and 192.168.14.208 have the last four bits of the host portion set to 0, making them subnet addresses.

The most likely problem is that the IP address of computer A is incorrect. Since computer A cannot ping RT_1, it suggests that there is an issue with its IP configuration. The other options, such as the trunk port, VLAN configuration, and management VLAN, do not directly affect the ability to ping RT_1. Therefore, the incorrect IP address is the most probable cause of the problem.

The subnet masks needed to fulfill the requirements of the three local networks are 255.255.254.0, 255.255.252.0, and 255.255.255.128.

- Network 1 requires 500 hosts, so a subnet mask of 255.255.254.0 will provide enough host addresses.
- Network 2 requires 100 hosts, so a subnet mask of 255.255.255.128 will provide enough host addresses.
- Network 3 requires 1000 hosts, so a subnet mask of 255.255.252.0 will provide enough host addresses.

These subnet masks ensure that each network has enough host addresses to accommodate the required number of hosts.

Distance vector routing protocols, such as RIP (Routing Information Protocol), operate by sending their routing tables to directly connected neighbors. These protocols periodically exchange information with their neighbors, sharing the entire routing table. Each router then uses this information to calculate the best path to reach a destination network. The routing updates are sent only to the directly connected neighbors, minimizing the amount of network traffic. This allows routers to efficiently update their routing tables and make informed forwarding decisions based on the received information.

The VLAN 99 is missing because it has not been manually entered into the VLAN database with the vlan 99 command. This means that the switch is not recognizing VLAN 99 as a valid VLAN and therefore it is not being displayed in the configuration and output.

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, allowing VLAN 20 traffic to pass between the switches. Since workstations in VLAN 20 cannot ping workstations in VLAN 20 on the opposite switch, it suggests that the VLAN 20 traffic is not being properly forwarded between the switches. Configuring the interfaces as trunk ports will enable the switches to pass traffic for multiple VLANs.

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The given 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 before PDU #2, which is an application layer PDU. PDU #3, which is a segment, is created before both PDU #1 and PDU #2.

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 through a console interface.
2) a protocol responsible for transporting electronic mail on TCP/IP networks and the Internet - This protocol is commonly known as SMTP (Simple Mail Transfer Protocol) and is used for sending and receiving emails.
3) a protocol that exchanges network management information between a network device and a management console - This protocol, known as SNMP (Simple Network Management Protocol), allows network administrators to monitor and manage network devices.