What is a common method of preventing brute force attacks on Linux systems?

Using SSH key pairs is a common method of preventing brute force attacks on Linux systems because it greatly enhances the security of remote logins compared to traditional password authentication. When utilizing SSH key pairs, authentication involves a private key stored securely on the client side and a corresponding public key placed on the server. This process eliminates the need for password transmission, making it extremely difficult for an attacker to guess or brute-force a private key.

In contrast, simply changing passwords regularly can help mitigate some risk but doesn't prevent brute force attempts if the same or weak passwords are used. While implementing a firewall provides an additional layer of security by filtering incoming and outgoing traffic, it does not specifically address authentication methods. Disabling user accounts entirely would prevent legitimate users from accessing the system, which is not a practical solution for maintaining accessibility and usability. Thus, the use of SSH key pairs stands out as the most effective solution against brute force attacks.