To mitigate DoS attacks, organizations often use which of the following?

Using redundant servers is an effective strategy for mitigating Denial of Service (DoS) attacks. The primary goal of a DoS attack is to overwhelm a system's resources, rendering it unavailable to legitimate users. By deploying redundant servers, an organization can distribute incoming traffic across multiple servers, thereby reducing the likelihood that any single server will be overwhelmed.

This load balancing creates a more resilient infrastructure, as traffic intended for a particular server can be rerouted to others that are available. This way, if one server is affected by an attack, the others can continue to operate, maintaining service availability. Additionally, this strategy can involve various configurations, such as failover mechanisms, where if one server goes down, another can take its place seamlessly.

In contrast, other options like application encryption and improved internal communications do not directly address the core issue of preventing or managing the excessive load caused by DoS attacks. While employee training is essential for overall security awareness, it is not a direct measure for mitigating the effects of these specific types of attacks. Thus, employing redundant servers is a straightforward and effective way to enhance an organization's defenses against DoS attacks.