Cisco CCNA Practice Test (200-301)

The correct configuration is the access-list entry that matches TCP traffic from the 192.168.10.0/24 network to host 10.1.1.1 on port 23. This entry specifically targets Telnet traffic (which uses TCP port 23) from the specified source network to the destination host. By matching this traffic, the administrator can effectively prevent Telnet sessions without affecting other services. The other options either have incorrect source and destination parameters, incorrect protocols, or target the wrong port, and therefore would not achieve the intended restriction.

Port security restricts the devices that can connect to a port based on their MAC addresses, enhancing network security.

By default, Cisco interfaces are administratively down. no shutdown activates the interface for network communication.

STP uses each switch's Bridge ID (BID) to elect the root bridge. The BID combines a 16-bit bridge-priority value with the switch's MAC address. The switch with the lowest numerical bridge-priority value wins the election. Only if two or more switches share the same priority does STP compare their MAC addresses, selecting the switch with the lowest MAC as the root. Therefore, the lowest bridge-priority value is the primary deciding factor, while the other attributes serve only as tiebreakers.

The value "192.168.10.0/24" represents the destination network and subnet mask in CIDR notation. This specifies the network to which packets are destined, known as the 'Prefix' in the routing table. Identifying the correct prefix is essential for routing decisions.

Southbound APIs enable the controller to communicate with and control the underlying network devices. They are responsible for translating the controller's instructions into configurations and policies that the devices can implement, effectively bridging the control plane and the data plane. Northbound APIs, in contrast, allow applications and services to interact with the controller to program the network, not directly with the devices. Options like 'Management APIs' and 'Configuration APIs' are generic terms and do not specifically describe the standardized interfaces used in controller-based architectures.

When a switch receives a frame with a destination MAC address that is not in its MAC address table, it floods the frame out of all other ports to locate the destination device. This is standard behavior for switch learning. Other options like a full MAC address table or hardware failure could cause issues, but they would typically result in dropped frames or system errors rather than frame flooding.

Routers use the longest prefix match when selecting a route to forward a packet. This means the router looks for the most specific route that matches the destination IP address. If multiple routes are available, the one with the longest network prefix (most matching bits) is chosen. Administrative distance and routing protocol metrics are considered only if multiple routes have the same prefix length.

Controller-based networks centralize network management by using a central controller that communicates with all network devices. This centralization allows for unified and automated configuration, policy enforcement, and management across the network, significantly reducing the need for manual configuration of individual devices. In contrast, traditional networks typically require network administrators to configure and manage each device separately, which can be time-consuming and error-prone, especially in large networks. By adopting a controller-based model, the enterprise can streamline network operations and reduce complexity.

FlexConnect mode (formerly H-REAP) supports local switching. If the WAN link to the controller fails, a FlexConnect AP enters standalone mode and locally bridges client traffic, so wireless users remain connected. Other modes such as Local, Monitor, and Sniffer shut down client data services when the controller connection is lost.

Remote access VPNs enable individual users to establish secure connections to a private network over the internet. This allows them to access network resources remotely, just like being directly connected to the network. Site-to-site VPNs, on the other hand, link entire networks at different locations, facilitating network-to-network communication.

Answer Description:

A vulnerability is a flaw or weakness in a system's design, implementation, or operation that could be exploited to violate the system's security policy. In this scenario, the security weakness that allows for SQL injection attacks is considered a vulnerability. A threat is anything that has the potential to cause harm to a system. An exploit is the method or technique used to take advantage of a vulnerability. Mitigation refers to the steps taken to reduce the risk associated with vulnerabilities and threats. Understanding these distinctions helps in effectively securing network resources.

WPA3 is the wireless security protocol that introduces new features to protect against brute-force dictionary attacks and provides forward secrecy. It replaces the Pre-shared Key (PSK) authentication method with Simultaneous Authentication of Equals (SAE), which is more secure. WPA2, although more secure than WPA, still uses PSK and lacks the additional protections introduced in WPA3. WPA is older and has known security vulnerabilities.

802.1Q is the IEEE standard that defines the method for frame tagging to support VLANs over trunk links between network devices. It inserts a VLAN tag into the Ethernet frame header, allowing switches to identify which VLAN a frame belongs to, thereby permitting multiple VLANs to share a single physical link.

ISL (Inter-Switch Link) is a Cisco proprietary protocol for VLAN tagging but is no longer widely used. 802.1X is a standard for port-based Network Access Control (NAC) and deals with authentication, not VLAN tagging. 802.3ad refers to link aggregation for combining multiple physical links into one logical link, but it does not handle VLAN tagging.

The underlay network is the physical infrastructure consisting of the actual routers, switches, and links that carry data packets. It provides the physical pathways for data transmission. The overlay network, on the other hand, is a virtual network built on top of the underlay network, enabling network virtualization and abstraction. The control plane manages network policies and decisions but does not provide physical pathways. The orchestration layer handles the coordination of network resources, not the physical data transmission.

The value of "enabled" is true, which is a Boolean data type in JSON. Booleans in JSON represent logical true or false values. The other options are incorrect: "true" in quotes would be a String, null represents the absence of a value, and 1500 is a Number.

WPA3 provides the highest level of security among the listed protocols by introducing stronger encryption algorithms and improved authentication methods, such as Simultaneous Authentication of Equals (SAE). WPA2, while still widely used, does not include these enhancements. WPA and WEP are older protocols with known vulnerabilities.

UDP (User Datagram Protocol) is the correct choice for applications like live video streaming where speed is critical, and some data loss can be tolerated. UDP does not establish a connection or provide reliable data delivery, which reduces overhead and latency.

In contrast, TCP (Transmission Control Protocol) provides reliable data delivery with error checking and retransmission but introduces more overhead and latency, making it less suitable for live streaming. SMTP (Simple Mail Transfer Protocol) and FTP (File Transfer Protocol) are application layer protocols used for email transmission and file transfers, respectively, and are not suitable for streaming applications.

Single-mode fiber is ideal for long-distance data transmission because it uses a single light path, minimizing signal attenuation and allowing for higher bandwidth over extended distances. Multimode fiber, while also a fiber optic medium, experiences modal dispersion, which limits its effective transmission distance. Copper cables, such as twisted pair and coaxial, are prone to higher attenuation and electromagnetic interference, making them less suitable for long-distance applications.

Configuring dynamic inside source translation using an address pool allows internal hosts to access external networks by dynamically mapping their private addresses to a pool of public addresses. This way, when an internal host initiates a connection, the router assigns an available public address from the pool without manual configuration for each host. Static inside source translation requires manual one-to-one mapping between private and public addresses, which the administrator wants to avoid. Port Address Translation (PAT) allows multiple internal hosts to share a single public address, which is unnecessary when multiple public addresses are available. Outside source translation is used for translating external addresses to internal addresses, which does not meet the requirement.