> Source: [sk175603](https://support.checkpoint.com/results/sk/sk175603)

# sk175603 - When a working host's MAC address is changed, the Security Gateway does not update its Linux ARP with the new MAC address

| Property | Value |
|----------|-------|
| Solution ID | sk175603 |
| Date Created | 2021-10-07 |
| Last Modified | 2026-06-03 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82, R81.20, R81.10 (EOS), R81 (EOS) |
| OS | Gaia |

## Symptoms

- When a working host's MAC address is changed, the Security Gateway does not update its Linux ARP with the new MAC address. The issue occurs if traffic initiated by the host uses the TCP protocol.

## Cause

1. When SecureXL forwards the traffic to the Security Gateway for PXL processing, the Security Gateway does not send an ARP request to learn the new host's MAC address.
2. In a scenario, when a DHCP client and a DHCP server communicate through the Security Gateway, the Security Gateway may not forward traffic to a DHCP client if its IP address was changed by the DHCP server.

## Solution

This solution requires authentication. Please log in to view the full solution.

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