> Source: [sk41898](https://support.checkpoint.com/results/sk/sk41898)

# sk41898 - Connecting multiple clusters running in Load Sharing Unicast mode results in MAC Address flapping on switches

| Property | Value |
|----------|-------|
| Solution ID | sk41898 |
| Date Created | 2009-05-21 |
| Last Modified | 2015-07-06 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |

## Symptoms

- In ClusterXL Load Sharing Unicast mode, the Pivot member does not forward the packets to the relevant non-Pivot member(s) via the right switch port.

## Cause

When several clusters in Load Sharing Unicast mode are connected to the same switch, all packets forwarded by the Pivot members in those clusters have the same Source MAC address. As a result, the switch detects the same MAC address on different ports, which causes port flapping on the switch.

## Solution

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