In the modern threat landscape, basic Access Control Lists (ACLs) and NAT are no longer enough. To truly secure a network, administrators must move from passive filtering to Active Defense. This blog explores how to utilize advanced firewall modules to hunt threats, baseline server behavior, and enforce internal compliance.
All examples shared in this blog are base on H3C Firewall F1000-AI-25
Real F1000-AI-25 machine
Active Defense is about anticipation and intelligence. Instead of waiting for a signature match, these tools monitor behavior and use external intelligence to block attacks before they land.
Threat Intelligence connects your firewall to global databases of known malicious actors. By leveraging real-time data from global security centers, your firewall stays ahead of evolving threats.
| Feature | Primary Target | Core Function |
|---|---|---|
| IP Reputation | Malicious IP Addresses | Blocks known C&C servers, botnets, and high-risk source IPs based on historical behavior. |
| URL Reputation | Malicious Web Links | Prevents users from accessing known phishing or malware-hosting websites. |
| Domain Reputation | Malicious Domain Names | Filters DNS requests to domains flagged for hosting malicious infrastructure. |
DGA (Domain Generation Algorithm) Inspection is a standout feature within this module.
The Concept: Malware often uses DGA to generate thousands of random domains daily to communicate with Command & Control (C2) servers.
Insight: In firewall feature picture, the DGA Inspection toggle allows the firewall to use intelligent inspection servers to identify these "random-looking" domains.
Example: If an infected internal PC tries to connect to a domain generated by a DGA, the firewall recognizes the algorithmic pattern and kills the connection, even if that specific domain isn't on a blacklist yet.
This module prevents any single entity from exhausting firewall or server resources.