> Source: [sk94565](https://support.checkpoint.com/results/sk/sk94565)

# sk94565 - Traffic is lost in ClusterXL High Availability when all cluster members are up because switches/routers send traffic to Standby member

| Property | Value |
|----------|-------|
| Solution ID | sk94565 |
| Date Created | 2013-08-24 |
| Last Modified | 2019-01-07 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |
| OS | Gaia |

## Symptoms

- * Traffic is lost when all members in ClusterXL High Availability are up (Active and all Standby members).  

  If Standby members are shut down / disconnected, then traffic flows as expected.

* Traffic capture on cluster members shows that network devices (switches, routers) send traffic to Standby member.

## Cause

Gratuitous ARP Request from Standby member is sent with MAC address of Standby member in the ARP packet payload.

When the Standby member sends an ARP Request on a specific interface, it puts the MAC address of the interface of the Active member in the ARP payload.  
If the Standby member does not have the MAC address for the relevant interface, then it adds the MAC address of Standby member into the ARP payload.  
This causes a problem for the network devices (switches, routers) because they believe that the next hop is the Standby member. Traffic is therefore sent to Standby member, which (by design) does not process any traffic.

## Solution

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