CompTIA Network+ Practice Test 2026 - Free Network+ Practice Questions and Exam Prep Guide

Using digital signatures through DNSSEC is the most effective method for securing DNS communications. DNSSEC, or Domain Name System Security Extensions, adds a layer of security to the DNS protocol by allowing DNS responses to be validated through cryptographic signatures. This process helps ensure that the data received in response to a DNS query has not been tampered with during transmission. By validating the authenticity and integrity of the DNS data through DNSSEC, users can trust that the responses they are receiving are legitimate and not subject to attacks such as spoofing or cache poisoning.

In contrast, transmitting in plaintext provides no security for the data, as it can be easily intercepted and altered by attackers. Implementing firewalls can enhance overall network security but does not specifically secure DNS communications. Similarly, while utilizing VPN services can encrypt traffic between a client and a server, it does not directly address the integrity and authenticity of the DNS data itself. Thus, DNSSEC stands out as the preferred method for securing DNS communications by addressing the specific vulnerabilities associated with DNS.