Computer Networking Ultimate Exam: Quiz!

Quality of Service (QoS) is indeed a technology that enables network optimization for specific traffic types. It allows prioritization of certain traffic, allocation of bandwidth, dropping of less important traffic during congestion, and efficient utilization of limited bandwidth in an IP WAN. Therefore, the statement "True" is an accurate representation of the explanation provided.

Ethernet and WLANs both use a form of carrier sense multiple access technology, which allows multiple devices to share the same communication medium. In Ethernet, this technology is called carrier sense multiple access collision detection (CSMA/CD), while in WLANs, it is called carrier sense multiple access collision avoidance (CSMA/CA). CSMA/CD is necessary for half-duplex Ethernet connections because it helps detect and handle collisions, while CSMA/CA is needed for WLAN connections because of their half-duplex operation. Therefore, the statement that Ethernet uses CSMA/CD and WLANs use CSMA/CA is true.

The explanation for the given correct answer is that marking alters bits within a frame, cell, or packet to indicate how the network should treat that traffic. However, marking alone does not change how the network treats a packet. The queuing tools in a switch or router can reference these markings and make decisions based on them. Therefore, the statement "Marking alone does not change how the network treats a packet" implies that marking alone is not sufficient to change the network's treatment of a packet, but it can influence the decisions made by queuing tools. Thus, the answer is true.

A packet filtering firewall is designed to examine the header of each packet of data that passes through it and make decisions on whether to allow or block the packet based on a set of rules known as Access Control Lists (ACLs). These rules define criteria such as source and destination IP addresses, port numbers, and protocols. If a packet matches the criteria defined in the ACL, it is allowed to pass through the firewall; otherwise, it is blocked. Therefore, the statement that a packet filtering firewall filters traffic based on ACL-like rules is true.

An omnidirectional antenna is designed to radiate power equally in all directions, similar to an isotropic antenna. This means that the antenna can transmit and receive signals from any direction without the need for repositioning. This characteristic makes omnidirectional antennas suitable for applications where signals need to be transmitted or received from multiple directions simultaneously, such as in wireless communication systems or broadcasting. Therefore, the statement that an omnidirectional antenna radiates power at relatively equal power levels in all directions is true.

The diagram below illustrates a scenario where an attacker intercepts communication between two parties, positioning themselves in the middle and impersonating each party to gather sensitive information or manipulate the data being transmitted. This type of attack is known as a man-in-the-middle attack.

Wardialing is not a security threat for WLANs. Wardialing is a technique used to scan telephone lines for modems, but it is not applicable to WLANs as they do not use telephone lines. Therefore, it does not pose a security threat to WLANs.

The ipconfig command is used to display IP address configuration parameters on a Windows PC. It provides information about the IP address, subnet mask, default gateway, and other network settings. Additionally, ipconfig can also be used to release and renew a DHCP lease, which is useful in troubleshooting network connectivity issues.

The three primary goals of network security are integrity, confidentiality, and availability. Integrity refers to the protection of data from unauthorized modification or alteration. Confidentiality involves ensuring that data is only accessible to authorized individuals or entities. Availability focuses on ensuring that network resources and services are accessible to authorized users when needed. These goals are essential for maintaining the security and functionality of a network.

The components of an SNMPv1 and SNMPv2c Network-Management Solution are SNMP manager, SNMP agent, and Management Information Base. The SNMP manager is responsible for controlling and monitoring the network devices. The SNMP agent is installed on the network devices and collects data and sends it to the SNMP manager. The Management Information Base (MIB) is a database that stores the information about the network devices and their configurations. Together, these components form a complete network management solution using SNMPv1 and SNMPv2c protocols.

The majority of a troubleshooter's efforts are spent in the problem diagnosis step. This is the step where the troubleshooter identifies the root cause of the problem by analyzing symptoms, gathering information, and conducting tests or experiments. Problem diagnosis is crucial in determining the appropriate solution and resolving the issue effectively.

The given answer, "Redundant Network with no Single point of failure," suggests that the WAN design represents a network that has redundant components to ensure high availability and fault tolerance. This means that even if one component fails, there are backup components in place to continue providing network services without any interruption or single point of failure.

A worm is not a piece of code that an end-user executes. A worm is a self-replicating malicious program that spreads through computer networks and does not require any user interaction to execute. It can exploit vulnerabilities in a system's security to infect other computers and can cause significant damage by consuming network bandwidth or deleting files. Therefore, the given statement is false.

A confidentiality attack attempts to make confidential data viewable by an attacker. However, it is not necessary for the attacker to make a copy of the data or crash the system in order to achieve this. Therefore, confidentiality attacks can be difficult to detect as they may not leave any obvious signs of compromise.

The statement is true because the administrative distance of a routing protocol represents the trustworthiness or credibility of that protocol. It is used to determine the preference of one routing protocol over another when multiple protocols are available for the same destination. A lower administrative distance indicates a higher believability, meaning that the routing information provided by that protocol is considered more reliable and accurate. Conversely, a higher administrative distance implies a lower level of trust in the routing information provided by the protocol.

The correct answer is WAP. WAP stands for Wireless Application Protocol, which is a protocol used for accessing information over a mobile wireless network. It is not a WLAN security standard, but rather a protocol for mobile internet access. WPA2, WPA, and WEP are all WLAN security standards used to secure wireless networks.

Access control lists are rules that are typically applied to router interfaces to specify permitted and denied traffic. These lists allow network administrators to control the flow of network traffic by filtering packets based on specific criteria such as source/destination IP addresses, protocols, and ports. By configuring access control lists, administrators can determine which traffic is allowed to pass through the router and which traffic should be denied, thereby enhancing network security and optimizing network performance.

The command "netstat" can be used to display information about current sessions, including source and destination IP addresses and port numbers. This command is commonly used in networking to troubleshoot and monitor network connections. It provides detailed information about active connections, listening ports, and network statistics.

The "tracert" command is used to trace the route that packets take from the source to the destination. It sends packets with increasing Time to Live (TTL) values, causing each router hop along the way to reply with an ICMP Time Exceeded message. This allows the command to report the round-trip time for each router hop, helping to identify network latency or connectivity issues.

A syslog-logging solution consists of two primary components: syslog servers and syslog clients. Syslog servers receive and store log messages from various devices and applications, acting as a centralized repository. Syslog clients, on the other hand, generate and send log messages to syslog servers. This client-server architecture allows for efficient log management and analysis, enabling organizations to monitor and troubleshoot their systems effectively.

Enabling SSID broadcast will not protect your wireless network. SSID broadcast is the process of broadcasting the network name so that devices can easily find and connect to it. However, this can make your network more vulnerable to attacks as it allows potential eavesdroppers to easily identify and target your network. To enhance security, it is recommended to disable SSID broadcast and use other measures such as a preshared key, MAC address filtering, and IEEE 802.1x authentication.

A time domain reflectometer (TDR) is used to identify the exact location of a break in a network cable. It works by sending a signal down the cable and measuring the time it takes for the signal to bounce back. By analyzing the time delay and intensity of the reflected signal, the TDR can pinpoint the exact location of the break. This is a valuable tool in troubleshooting network cables as it allows technicians to quickly and accurately locate and repair breaks, minimizing downtime and improving network performance.

The Physical layer of the OSI model is foundational to all the other layers. It is responsible for the transmission and reception of raw data bits over a physical medium. The other layers build upon this layer to provide more complex functionalities such as error detection, routing, and application support. Without a solid physical layer, the higher layers would not be able to communicate effectively. Therefore, the correct answer is False.

An application log contains information about the software running on the operating system. It includes details such as the applications that are currently running, their status, any errors or warnings encountered, and other relevant information related to the software. This log helps in troubleshooting and monitoring the performance of the applications. It provides insights into the functioning of the software and aids in identifying any issues or improvements needed.

Crosstalk can occur when an analog connection creates an electromagnetic field around its conductors, inducing its waveforms on a nearby analog connection. This can result in interference and signal degradation, affecting the quality of the transmission.

The wireless device marked X in the image is a wireless router. A wireless router is a device that allows multiple devices to connect to a network and share an internet connection wirelessly. It acts as a central hub, connecting devices to the internet and also allowing communication between devices on the same network.

The nslookup command is used to resolve a Fully Qualified Domain Name (FQDN) to an IP address. It is a network administration tool that allows users to query the Domain Name System (DNS) to obtain information about domain names, including their corresponding IP addresses. By using nslookup, users can easily find the IP address associated with a specific FQDN.

DFSS is not a variation of spread-spectrum technology. This is because DFSS is not a commonly used or recognized acronym in the field of spread-spectrum technology. DSSS (Direct Sequence Spread Spectrum), OFDM (Orthogonal Frequency Division Multiplexing), and FHSS (Frequency Hopping Spread Spectrum) are all well-known and widely used variations of spread-spectrum technology.

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When a wireless channel uses more than one frequency, the transmission method is called spread spectrum. This technique spreads the signal across a wide range of frequencies, which helps to improve the reliability and security of the wireless communication. It allows multiple users to share the same frequency band without causing interference, and it also provides resistance against jamming and eavesdropping. Spread spectrum is commonly used in technologies like Wi-Fi and Bluetooth to ensure efficient and robust wireless communication.

The correct answer is "Undirectional, Omnidirectional". These two options, undirectional and omnidirectional, refer to different types of wireless antennas based on their coverage capabilities. Undirectional antennas transmit and receive signals in a specific direction, providing focused coverage in a particular area. On the other hand, omnidirectional antennas radiate signals in all directions, providing a 360-degree coverage pattern. Therefore, both undirectional and omnidirectional antennas are categories of wireless antennas that are based on coverage.

HSRP (Hot Standby Router Protocol) is a Cisco proprietary approach to first-hop redundancy. It is a protocol that allows multiple routers to work together in a group, with one router acting as the active router and the others as standby routers. The active router handles all traffic by default, and if it fails, one of the standby routers takes over seamlessly. HSRP provides redundancy and high availability for network connections, ensuring uninterrupted connectivity in case of router failures.

The effective bandwidth in the WAN diagram is 256 kbps. This means that the maximum data transfer rate in the wide area network is 256 kilobits per second. This is the amount of data that can be transmitted within a given time frame.

The correct answer is ifconfig. This command is used on UNIX/Linux machines to display the IP address configuration. It provides information about the network interfaces and their configurations, including IP addresses, netmasks, and other related details.

A Protocol Analyzer is also known as a network sniffer because it is a tool used to capture and analyze network traffic. It allows users to monitor and analyze the data packets flowing through a network, providing insights into network performance, troubleshooting network issues, and identifying potential security threats. The term "network sniffer" is commonly used to describe this type of tool due to its ability to "sniff" or capture network packets for analysis.

802.11b operates at a maximum bandwidth of less than 20Mbps. This standard was introduced in 1999 and operates in the 2.4GHz frequency range. It provides a maximum data rate of 11Mbps, which is lower compared to the other options listed. 802.11n, 802.11a, and 802.11g, on the other hand, offer higher maximum data rates and improved performance. 802.11n can reach up to 600Mbps, 802.11a can reach up to 54Mbps, and 802.11g can reach up to 54Mbps as well.

The ARP command is used to see the MAC address associated with an IP address. ARP stands for Address Resolution Protocol, and it is responsible for mapping an IP address to its corresponding MAC address on a local network. By using the ARP command, one can retrieve the MAC address of a specific IP address, which can be useful for troubleshooting network connectivity or identifying devices on a network.

CARP and HSRP are both examples of Layer 3 redundancy protocols. These protocols provide redundancy at the network layer by allowing multiple routers to share a virtual IP address. In the event of a failure of the active router, the standby router takes over the virtual IP address, ensuring continuous network connectivity. This redundancy is achieved through the use of election processes and virtual MAC addresses. Collective standby, active-standby, and active-active are not specifically mentioned as Layer 3 redundancy modes and therefore are not the correct answers.

The "ping" command is one of the most commonly used command-line commands. It can be used to check IP connectivity between two network devices. Multiple platforms (for example, routers, switches, and hosts) support the "ping" command.

The "route" command can display a PC's current IP routing table. It is a command-line tool used in networking to view and manipulate the routing table, which contains information about how data packets should be forwarded from one network to another. By using the "route" command, users can see the current routing entries and their associated destination networks, gateway addresses, and interface names. This information is crucial for troubleshooting network connectivity issues and configuring routing protocols.

SNMP (Simple Network Management Protocol) is a protocol used for managing and monitoring network devices. The three broad categories of SNMP message types are SNMP GET, SNMP SET, and SNMP Trap.

- SNMP GET is used by a management system to retrieve information from a network device.
- SNMP SET is used to modify or update the configuration of a network device.
- SNMP Trap is a notification sent by a network device to a management system to inform about a specific event or condition.

These three message types play a crucial role in the communication between the management system and network devices in SNMP-based networks.

The correct answer is A-Firewall, B-Syslog Server, C-Switch, D-Router. This is because the picture shows a firewall (A) connected to a syslog server (B), a switch (C), and a router (D). The syslog server is responsible for collecting and storing log messages from various network devices, including the firewall, switch, and router. The switch is used to connect multiple devices within a network, and the router is responsible for routing network traffic between different networks.

AES and 3DES are both examples of symmetric encryption because they use the same key for both encryption and decryption. In symmetric encryption, the sender and receiver use a shared secret key to encrypt and decrypt the data. RSA and PGP, on the other hand, are examples of asymmetric encryption, where a pair of keys (public and private) are used for encryption and decryption.

The statement explains that availability and reliability are not the same. While an available network does not drop many packets, a reliable network is not only available but also up and operational. Therefore, the statement is false.

Active-standby and active-active are both modes of Network Interface Card (NIC) redundancy. In active-standby mode, there is a primary NIC that handles all the network traffic, while the standby NIC remains idle until the primary NIC fails. When the primary NIC fails, the standby NIC takes over and becomes active. This mode provides failover capability and ensures continuous network connectivity. On the other hand, in active-active mode, both NICs are active simultaneously and share the network traffic load. This mode provides load balancing and redundancy, as both NICs can handle network traffic independently.

The correct answer is TCP SYN Flood. This type of availability attack involves overwhelming a target server with a flood of TCP SYN requests, exhausting its resources and causing a denial of service. The diagram likely depicts the process of multiple TCP SYN packets being sent to the server, which it tries to respond to by sending SYN-ACK packets. However, the attacker does not complete the handshake process, leaving the server with a backlog of unfinished connections and rendering it unable to handle legitimate requests. This results in a denial of service for legitimate users.

The design issue with this wireless network is that the channels being used interfere with one another. This can lead to poor performance and connectivity issues as the overlapping channels cause interference and congestion. It is important to properly plan and allocate channels in order to optimize the wireless network's performance and minimize interference.

Active-active is the best term to describe the given definition because in an active-active configuration, both network interface cards (NICs) are active simultaneously, meaning they are both actively processing and transmitting data. Each NIC also has its own unique MAC address, which allows for separate identification and communication. This configuration provides redundancy and load balancing, as both NICs share the workload and can handle traffic independently.

A throughput tester is a tool or device used to observe how a network performs under heavy load. It helps in measuring the amount of data that can be transmitted over a network within a given time period. By simulating heavy traffic or high data transfer rates, the tester can identify any bottlenecks or performance issues in the network. This information is valuable for network administrators to optimize the network's performance and ensure smooth operation even during peak usage.

The correct answer is traceroute. Traceroute is a command used on Linux/UNIX machines to display the router hops to the destination IP address. It shows the path that packets take from the source to the destination, including the IP addresses of the routers along the way. This can be useful for troubleshooting network connectivity issues and analyzing network performance.