RADIUS

Implementing strong password policies is the best security measure that should be put in place to prevent a security breach from reoccurring due to a weak RADIUS password. With strong password policies, it will be difficult for attackers to guess the password used in RADIUS The other options are less desirable for the following reasons: - Disabling RADIUS is not a practical solution as RADIUS (Remote Authentication Dial-In User Service) is a networking protocol that provides centralized Authentication, Authorization, and Accounting (AAA or Triple A) management for users who connect and use a network service. So, disabling it would mean eliminating a crucial element in network security - Restricting access to RADIUS logs would not solve the core problem, which is the weak password. Although securing RADIUS logs is a good security measure, in this case, it wouldn’t prevent an attacker who has already gained access through a weak password - Changing the RADIUS port may evade some low-level threats but it does not address the fact that the attacker was able to gain access due to a weak password. Port change can be considered as 'Security Through Obscurity', and it is not a reliable security strategy and cannot be a substitute for strong password policies.

The correct answer is the AAA server. RADIUS(Remote Authentication Dial-In User Service) is an AAA (Authentication, Authorization, and Accounting) protocol for applications such as network access or IP mobility. It is used to manage user profiles in a central database that can be shared among different network devices to enforce access control. Therefore, in this case, if a network admin wants to use RADIUS to manage user accounts for various network devices, he/she should configure the AAA server to handle the RADIUS authentication.

The other options are incorrect because the NTP(Network Time Protocol) server is used to synchronize the clocks of computers over a network, the file server provides a location on a network where multiple users can store and access files, and the DHCP(Dynamic Host Control Protocol) server is responsible for assigning IP addresses to computers on a network. None of these servers handle RADIUS authentication.

The primary advantage of using RADIUS proxy for authentication requests in a scenario involving remote locations is 'Centralized authentication management'. RADIUS proxy facilitates all authentication requests to go through a central location, which simplifies the management of user access by maintaining a single cohesive list of users and their access rights. 'Improved load balancing' while could be a part of a RADIUS proxy solution, it is not its primary advantage. The same applies to 'Increased network security'. Although a RADIUS proxy can contribute to increasing the security level of a network, it's not its main advantage. 'Reduced RADIUS server traffic' might not necessarily be true, as the RADIUS proxy must process all authentication requests it receives, potentially increasing traffic.