> Source: [sk184183](https://support.checkpoint.com/results/sk/sk184183)

# sk184183 - Security Gateway/Cluster member becomes unresponsive and drops traffic

| Property | Value |
|----------|-------|
| Solution ID | sk184183 |
| Date Created | 2025-10-16 |
| Last Modified | 2026-01-06 |
| Technical Level | General |
| Products | Security Gateway |
| Versions | R82, R81.20 |
| OS | Gaia |

## Symptoms

- * Security Gateway/Cluster member becomes unresponsive and drops traffic.

* Frequent and random status changes and failovers occur in a ClusterXL, VSX, or Scalable Platform environments when HyperFlow is enabled, resulting in outages and loss of connectivity.

* Logs in the */var/log/messages* file show the Active Cluster member state changing to Down because no CCP packets are received, for example:   

  `
  [DATE TIME][fw4_1];[vs_0];[HOSTNAME]: State change: ACTIVE! -> DOWN | Reason: Interface Sync is down (Cluster Control Protocol packets are not received)`

* The $FWDIR/log/fwk.elg file logs show lock-up messages on Firewall instances, but the CPU utilization remains low, for example:  

  `
  [DATE TIME][fwk4];[vs_0];[instance_8];[18143];Warning:cp_timed_blocker_handler: A handler [0x4116e0] blocked for 3 seconds.`  
  `
  [DATE TIME][fwk4];[vs_0];[instance_8];[18143];Warning:cp_timed_blocker_handler: Handler info: Library [fwk], Function offset [0x116e0].`  
  `
  [DATE TIME][fwk4];[vs_0];[instance_11];[18146];Warning:cp_timed_blocker_handler: A handler [0x4116e0] blocked for 7 seconds.`  
  `
  [DATE TIME][fwk4];[vs_0];[instance_11];[18146];Warning:cp_timed_blocker_handler: Handler info: Library [fwk], Function offset [0x116e0].`  
  `
  [DATE TIME][fwk4];[vs_0];[instance_13];[18148];Warning:cp_timed_blocker_handler: A handler [0x4116e0] blocked for 7 seconds.`  
  `
  [DATE TIME][fwk4];[vs_0];[instance_13];[18148];Warning:cp_timed_blocker_handler: Handler info: Library [fwk], Function offset [0x116e0].`

## Cause

The HyperFlow feature (see [R82 Performance Tuning Admin Guide](https://sc1.checkpoint.com/documents/R82/WebAdminGuides/EN/CP_R82_PerformanceTuning_AdminGuide/Default.htm "R82 Performance Tuning Admin Guide") \> HyperFlow section[](https://sc1.checkpoint.com/documents/R82/WebAdminGuides/EN/CP_R82_SecurityGateway_Guide/Content/Topics-FWG/HyperFlow.htm)) is enabled by default on R81.20 and higher versions. It triggers soft lock-ups, causing the Firewall instances to become locked, delaying or failing the processing and forwarding of Cluster Control Protocol (CCP) packets.  
This in turn causes cluster-state flapping and failover.

## Solution

This problem was fixed. The fix is included in:

* [Jumbo Hotfix Accumulator for R82](https://sc1.checkpoint.com/documents/Jumbo_HFA/R82/Default.htm) starting from Take 44
* [Jumbo Hotfix Accumulator for R81.20](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.20/Default.htm) starting from Take 119

If you choose not to upgrade, Check Point can supply a **Hotfix** . [Contact Check Point Support](https://www.checkpoint.com/support-services/.contact-support/) to get a Hotfix for this issue.  
A Support Engineer will make sure the Hotfix is compatible with your environment before providing the Hotfix.  
For faster resolution and verification, please collect [CPinfo files](http://supportcontent.checkpoint.com/solutions?id=sk92739) from the Security Management Server and Security Gateways involved in the case.

**Hotfix installation instructions:**   
Refer to [sk168597 - How to install a Hotfix](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk168597).

<br />

If you cannot install the hotfix, you can use this **workaround** :  

1. **Disable the Kernel Parameter:**   
   1. Run the command: `# fw ctl set -f int mux_dmd_use_on_non_ef_instance 0`
   2. Re-enable the HyperFlow feature per [sk178070](https://support.checkpoint.com/results/sk/sk178070)
   3. Reboot the Security Gateway to apply the changes.
2. **Verify the change:**   
   Run: `# fw ctl get int mux_dmd_use_on_non_ef_instance`  
   The expected output: `mux_dmd_use_on_non_ef_instance = 0`

<br />

**Note:**This solution restricts HyperFlow to interact only with CPUs handling relevant connections, resolving lock-up and CCP delay issues.

---

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