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Static Route Validity Issue

xonivre Lv1  Posted 2026-Sep-24 14:30


Dear Sangfor Expert,

I am a new user of the Sangfor NSF-1100A-I, and I would like to request your assistance in troubleshooting an issue with my WAN connections and static routes.

1. Static Route Validity Issue

Under Network → Static Routes, I noticed that the default routes for both of my ISPs are showing “Invalid” under the Validity column:

ISP1 – ether1
ISP2 – ether2


My question is: Is there a recommended configuration or troubleshooting procedure to make these routes show “Valid”?

I would appreciate a step-by-step explanation because I am still learning how routing works on the Sangfor platform.

2. Recurring Internet Disconnection

I also experience an internet interruption almost every morning at approximately 8:00 AM.

During the incident:

Internet connectivity is lost for users.
The interruption lasts approximately 3 minutes.
Internet connectivity then returns to normal automatically.
Under Network → Policy Base Routes, I observed that the Link State of both ISP1 and ISP2 was showing “Fault.”

I would like to know whether the Invalid status under Static Routes could be related to the recurring internet disconnection.

2. Additional Testing and Observations

I also observed that when I physically disconnect ISP2 (ether2), ISP1 becomes Valid and the network becomes stable.

This makes me suspect that there may be an issue involving ISP2, WAN link detection, Policy-Based Routing, or the interaction between the two WAN connections. However, I would like Sangfor Support to verify this rather than make assumptions.


Best regards,

Ervin

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rizzuan Lv2  Posted 2026-Sep-24 20:57
  
Hi Ervin,

Based on your observations, I would focus first on the WAN link detection and the relationship between the two ISP interfaces, rather than changing the static routes immediately.

Since ISP1 becomes Valid when ISP2 is disconnected, I would compare the link detection configuration of both interfaces:

Check the configured gateway and whether the next-hop is reachable from each WAN interface.
Check the WAN Link Detection method, detection target IP and detection interval.
Check whether both ISP interfaces use the same or overlapping detection targets.
Check the link detection logs around 08:00 AM and compare them with the Policy-Based Routing logs.
Check whether any scheduled task, policy change, or health-check event occurs around the same time.
Temporarily disconnect ISP2 and observe whether ISP1 remains stable during the normal 08:00 AM window.

The fact that both WAN links report Fault at approximately the same time makes me particularly interested in the link-detection mechanism or something affecting both WAN paths, rather than a problem with only one ISP.

If possible, I would capture the WAN link status and detection logs immediately when the issue occurs. That should help determine whether the firewall is actually losing connectivity or only marking the routes as invalid because the health-check target becomes unreachable.

I would avoid changing the routing configuration until the link detection result is confirmed, so we can isolate the actual cause first.
Andre Agave Lv1  Posted 2026-Sep-24 17:58
  
Thank you for providing the detailed information. Based on your description, the "Invalid" status of the static routes may indeed be related to the link detection mechanism and could potentially explain why both WAN links are reported as Fault during the morning interruption.

1. About the Static Route "Invalid" Status

Normally, a static route may show Invalid when the next-hop gateway is unreachable or when the associated WAN interface does not pass the configured link-health detection.

Please verify the following:

Confirm that the configured gateway IP for ISP1 and ISP2 is correct and reachable.
Check whether the WAN interfaces can successfully ping their respective gateways.
Review the Link Detection / ISP Health Check configuration:
Detection target IP address
Detection interval
Failure threshold
Verify that there are no overlapping default routes with conflicting priorities or metrics.

A useful test is:

Disable ISP2 temporarily.
Observe whether ISP1 immediately changes to Valid.
Re-enable ISP2 and check whether the Invalid status returns.

Since you mentioned that ISP1 becomes Valid when ISP2 is disconnected, this may indicate a problem with ISP2 connectivity, gateway reachability, route competition, or WAN health-check configuration.

2. About the Daily 08:00 AM Internet Interruption

Since both ISP links show Fault simultaneously during the incident, I would recommend checking:

WAN Link Detection logs
ISP gateway reachability logs
Scheduled tasks or maintenance jobs around 08:00 AM
PPPoE reconnect events (if applicable)
ISP service stability during that timeframe

If both links enter the Fault state at the same moment, the issue might be related to:

Health-check target becoming unreachable
DNS-based detection failure
Routing failover configuration
External ISP behavior
3. Additional Information Requested

To assist further, could you please provide:

Screenshot of Network → Static Routes
Screenshot of Network → Policy Based Routes
Screenshot of WAN Link Detection / ISP Detection settings
Interface type used by ISP1 and ISP2 (Static IP, DHCP, PPPoE, etc.)
Firmware version of the NSF-1100A-I

These details will help determine whether the issue is caused by route validation, WAN health checks, or failover configuration.

Based on your observation that disconnecting ISP2 causes ISP1 to become Valid and stable, ISP2 or its health-check configuration would be the first area I would investigate.

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