Which of the following services is essential for network security on Alibaba Cloud?

The chosen answer points to the Alibaba Cloud Web Application Firewall as a crucial service for network security. This service specifically protects web applications from various threats, including SQL injection, cross-site scripting, and other vulnerabilities that can be exploited by attackers. By monitoring and controlling incoming traffic to web applications, it helps ensure that only legitimate traffic is allowed while malicious activities are blocked.

This is particularly important for businesses that rely heavily on their online presence, as securing web applications is a fundamental aspect of maintaining customer trust and safeguarding sensitive data. The Web Application Firewall employs rules and policies to mitigate threats, offering a layer of protection tailored to the unique risks faced by applications exposed to the internet.

While other services listed also play significant roles in enhancing network security, the Web Application Firewall specifically focuses on securing the web application layer, which is often where vulnerabilities are exploited. This specialized functionality makes it essential for anyone looking to fortify their cloud infrastructure against web-based threats.