A cloud firewall blocks a request after interception primarily to protect the network and applications from potential threats, unauthorized access, or malicious activities. Firewalls analyze incoming and outgoing traffic based on predefined security rules, such as IP addresses, ports, protocols, or signatures of known attacks. If a request violates these rules or exhibits suspicious behavior, the firewall intervenes to prevent it from reaching its destination.
For example, if a request originates from a known malicious IP address or contains SQL injection patterns, the firewall will block it to safeguard the system. Similarly, if a request attempts to access a restricted port or service, the firewall will deny it to maintain security policies.
In cloud environments, firewalls like Tencent Cloud Security Firewall provide advanced threat detection and prevention capabilities. They can integrate with other security services, such as intrusion detection systems (IDS) and web application firewalls (WAF), to enhance protection. For instance, Tencent Cloud's WAF can block requests containing cross-site scripting (XSS) or other web-based attacks, ensuring applications remain secure.