> Source: [sk183530](https://support.checkpoint.com/results/sk/sk183530)

# sk183530 - Traffic interruption when traffic is forwarded through a Virtual Switch in a Virtual System Load Sharing setup with a distribution of Virtual Systems

| Property | Value |
|----------|-------|
| Solution ID | sk183530 |
| Date Created | 2025-06-04 |
| Last Modified | 2025-06-05 |
| Technical Level | General |
| Products | Scalable Platforms |
| Versions | R81.20 |
| OS | Gaia |

## Symptoms

- In a Virtual System Load Sharing (VSLS) configuration where active Virtual Systems (VSs) are distributed across multiple chassis, traffic interruptions occur when packets are forwarded through a Virtual Switch (VSW).

Additional Observations:

* No packet drops are seen on the active VSs.
* However, the VSW fails to forward traffic to the target VS.
* Running the command `bridge fdb show` shows some Forwarding Database (FDB) entries marked as permanent (Do Not Update).

## Cause

In rare scenarios, an FDB entry may be incorrectly marked as `Do Not Update`, preventing proper MAC learning or forwarding. This can result in a traffic outage that may last several minutes, especially after a VS failover from one chassis to another in a VSLS setup.

## Solution

This problem was fixed. The fix is included starting from:

* [Jumbo Hotfix Accumulator for R81.20](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.20/Default.htm) starting from Take 101

Check Point recommends to always upgrade to the [Recommended version](https://support.checkpoint.com/results/sk/sk95746) ([Security Gateway](https://support.checkpoint.com/product/73) / [VSX](https://support.checkpoint.com/product/359) / [Security Management Server](https://support.checkpoint.com/product/184) / [Multi-Domain Security Management Server](https://support.checkpoint.com/product/166) / [SmartConsole](https://support.checkpoint.com/product/191)).

If you choose not to upgrade, [contact Check Point Support](https://www.checkpoint.com/support-services/contact-support/) to get a Hotfix for your version.

A Support Engineer will make sure the Hotfix is compatible with your environment before providing it.  
For faster resolution and verification, collect these files:

1. [CPinfo](https://support.checkpoint.com/results/sk/sk92739) file from the Management Server involved in the case.
2. [CPinfo](https://support.checkpoint.com/results/sk/sk92739) file from the Security Gateway / each Cluster Member involved in the case.

**Hotfix installation instructions:**   
Refer to [sk168597 - How to install a Hotfix](https://support.checkpoint.com/results/sk/sk168597).

---

# Agent Instructions

This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products.

## Navigating This Knowledge Base

- **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt)
- **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml)
- **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}`
- **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content