How to Fix Internet Access Issues on Sangfor NGAF (Step-by-Step Troubleshooting Guide)
  

Muhammad Abid Lv1Posted Dec-12-2025 14:23

Overview

Many users face internet access problems on Sangfor NGAF such as no browsing, slow internet, or intermittent connectivity. These issues are usually caused by routing, DNS, policy misconfiguration, or session-related problems.
This guide covers simple and effective troubleshooting steps that every admin can follow.

1️⃣ Check Basic Connectivity

Go to: Network → Interface

Ensure WAN port is UP

Verify IP address, gateway, and DNS

Perform a ping test from the firewall
→ Diagnostics → Ping → 8.8.8.8

If ping fails, it’s likely an ISP issue or an incorrect gateway.

2️⃣ Verify Routing

Go to: Network → Routing → Route Table

Make sure the default route (0.0.0.0/0) is pointing to the correct ISP

If multiple WAN links exist, check the route priority and weight

Wrong routing = no internet.

3️⃣ Check Anti-DoS / Anti-DDoS Policies

Sometimes strict Anti-DoS rules block normal user traffic.
Go to: Security → Anti-DoS

Check alarms and blocked traffic

Temporarily add the user subnet to the Exception List

Adjust traffic thresholds if required

4️⃣ Review Application Control Policy

A very common reason for internet blocking:

Uncategorized traffic is blocked

"Web Browsing" category is not allowed properly

Go to: Security → Application Control → Policy

Ensure your rule allows Web Browsing

Review content filtering categories

5️⃣ Fix DNS Issues

If the internet connects but websites load slowly or fail to resolve, DNS is the cause.

Recommended DNS:

Primary: 8.8.8.8

Secondary: 1.1.1.1

Configure in: Network → Interface → DNS Settings

6️⃣ Clear Session Table / NAT Table

Old sessions sometimes cause congestion or traffic blocking.

Run:

diagnose system session clear
diagnose system nat clear


(Use during low-usage hours)

7️⃣ Check URL Filtering Logs

Go to: Log Center → Web Filtering

You can see the exact block reason, such as:

Category block

Reputation block

DNS tunneling

Botnet traffic

Suspicious requests

Create allow/exception rules based on the log details.

8️⃣ Additional Quick Fixes

✔ Flush DNS cache
✔ Restart WAN interface
✔ Verify ISP bandwidth
✔ Temporarily disable QoS (to test)
✔ Check license status (expired licenses block features)

Conclusion

By following these 8 troubleshooting steps, you can solve 90% of internet access and browsing issues on Sangfor NGAF.
This guide is especially useful for IT administrators and network engineers responsible for daily operations.

Like this topic? Like it or reward the author.

Creating a topic earns you 5 coins. A featured or excellent topic earns you more coins. What is Coin?

Enter your mobile phone number and company name for better service. Go

Humayun Ahmed Lv3Posted Dec-12-2025 17:49
  
Thanks to share!