Routers

Correct Answer: Review and adjust Quality of Service (QoS) settings on the routers

The best solution to improve connectivity when a network is experiencing poor performance is to 'Review and adjust Quality of Service (QoS) settings on the routers'. Quality of Service is a feature of routers and switches which prioritizes traffic so that more important traffic can pass first. This feature can be adjusted to ensure optimal performance. The other solutions proposed are not the best options. 'Adding more switches to the network' may not necessarily improve connectivity issues, it might even complicate the network. 'Upgrading the server's network card' can be a solution if the server network card is causing a bottleneck, but given only the issue of poor connectivity, this would not be the first step to take. Similarly, 'Replacing the routers with higher capacity models' is a costly solution and should only be considered after simpler and cost-efficient solutions have been ruled out which in this case is to adjust QoS settings.

Correct Answer: IPsec Site-to-Site VPN

The best way to connect two office locations using an encrypted connection is to set up an IPsec Site-to-Site VPN on their routers. Internet Protocol Security (IPsec) is a protocol suite that encrypts the entire IP packet of a communication session, thus ensuring the security of data transmitted between the two locations. On the other hand, Access Control Lists (ACLs) are used to filter traffic and manage network security but do not offer encryption. NAT Overload, also known as Port Address Translation (PAT), is used for conserving public IP addresses but does not provide a secure connection between different office locations. Dynamic Routing involves algorithms that dynamically respond to changes in the network, but it also does not secure the network connection between two sites. Therefore, to connect two office sites securely, IPsec Site-to-Site VPN is the correct option.

Correct Answer: Access Control List

The best answer is 'Access Control List'. In networking, an Access Control List (ACL) enables a network administrator to filter traffic by allowing and denying permissions based on IP address. This makes it the reasonable choice for allowing only specified IP addresses to access specific resources. On the other hand, 'Router-on-a-Stick' is a method of inter-VLAN routing where a single interface in a router is used as a trunk link to a switch, 'Dynamic NAT' is used to map unregistered IP addresses to registered IP addresses, not for controlling access to resources. 'Static Routing', while it does involve IP addresses, it doesn't have the specificity needed to restrict access to certain resources by IP address.