> Source: [sk176285](https://support.checkpoint.com/results/sk/sk176285)

# sk176285 - In ClusterXL Load Sharing in Unicast mode, ESP VPN fails after pivot cluster member failover

| Property | Value |
|----------|-------|
| Solution ID | sk176285 |
| Date Created | 2021-11-15 |
| Last Modified | 2023-12-13 |
| Technical Level | General |
| Products | Security Gateway |
| Versions | R81.10 (EOS), R81 (EOS) |

## Symptoms

- * In a Cluster XL configuration with Load Sharing in Unicast mode, Encapsulating Security Protocol (ESP) VPN traffic fails.
* The *orig_route_params* kernel table contains the wrong MAC address for the VPN peer.
* The output of the `tcpdump` command shows that the cluster sends traffic to the wrong destination MAC address.

## Cause

Packets arrive to the pivot cluster member. Then, the pivot cluster member forwards most packets to the non-pivot cluster members for inspection on the same interface where the packets arrived. To avoid MAC confusion, the pivot cluster member changes the source MAC address.   

When a VPN connection is established and accelerated, the pivot cluster member stores the original source MAC address of an incoming ESP packet in the *orig_route_params* kernel table*.* When a non-pivot cluster member receives a VPN packet, the non-pivot cluster member restores the original source MAC address to *orig_route_params.* Then, the non-pivot cluster member uses the original source MAC address for response ESP packets.  

During failover of the pivot cluster member, for a short time the pivot cluster member continues to forward packets from the upstream device to a non-pivot cluster member. The pivot cluster member does not update the table *orig_route_params* . As a result, the non-pivot cluster member adds a non-existent MAC address to *orig_route_params.*Then, cluster members use the non-existent MAC address as the destination MAC address for ESP packets.

## Solution

[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](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk92739) files from the Security Management 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).

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