From Alert to Action: How to Investigate Suspicious Traffic on Sangfor NGAF

In modern network environments, detecting a security alert is only the first step. The real challenge is understanding **what happened, why it happened, and what action should be taken next**.

When Sangfor NGAF generates a suspicious traffic or security event, I follow a structured investigation approach:

1. Identify the Source & Destination**

Check the source IP, destination IP, and determine whether the traffic is internal or external.

2. Analyze Ports & Protocols**

Review the destination port, protocol, and application involved. Unexpected services or unusual ports can be an important indicator.

3. Check the Matched Security Policy**

Identify which firewall/security policy handled the traffic and whether the traffic was allowed, blocked, or monitored.

4. Review Security Events**

Correlate the event with IPS, Anti-DDoS, Anti-Malware, or other security modules to understand the nature of the threat.

5. Investigate Traffic & Session Logs**

Look for repeated connections, unusual traffic volume, scanning behavior, or multiple destinations contacted by the same source.

6. Correlate Multiple Events**

A single alert may not tell the complete story. Multiple events from the same source or against the same destination can reveal a larger attack pattern.

7. Take Appropriate Action**

Depending on the investigation, possible actions include blocking the source IP, modifying the security policy, isolating the affected host, or continuing monitoring.

8. Verify After Mitigation**

After taking action, check the logs again to confirm that the suspicious activity has stopped and that legitimate traffic is still working normally.

The key takeaway

A security alert should not simply be treated as **“Blocked = Problem Solved.”**

A better approach is:

Detection → Investigation → Correlation → Response → Verification**

This process helps security teams move from simply reacting to alerts toward **proactive threat investigation and defense**.

How do you investigate suspicious traffic on your NGAF?**

Do you start with Security Events, Traffic Logs, or Policy Logs?

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