# Traffic does not pass through the GRE tunnel when Virtual MAC (VMAC) is enabled

## Product
**Cluster:** XL  
**Version:** R80.40 (EOS), R81 (EOS), R81.10 (EOS), R81.20  
**OS:** Gaia  
**Platform:** All  
**Last Modified:** 2023-03-22

## Symptoms

- Connections over the GRE tunnel fail when the cluster is configured with Virtual MAC (VMAC).
- These appear when ClusterXL debug is enabled (`-m cluster + drop select` (while fwha_dprint_io=1)):

```
fwha_select_should_drop_vmac: dropping packet to IP_OF_GRE_INERFACE (BOGUS_MAC_ADDRESS) on GRE_INTERFACE_NAME (GRE_INTERFACE_NUMER);
```

**Example**:  
```
fwha_select_should_drop_vmac: dropping packet to 10.70.0.3 (45:00:00:4C:A6:B7) on gre20 (13);
```

## Cause

When VMAC is enabled, the cluster layer only allows traffic where the destination MAC is the VMAC or the physical interface MAC address.

As a GRE decapsulated packet does not hold Layer 2 information (source MAC and destination MAC), the cluster layer does not accept these packets, and the connections fail.

## Solution

This problem was fixed. The fix is included in:

- [Jumbo Hotfix Accumulator for R81.20](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.20/Default.htm) starting from Take 8
- [Jumbo Hotfix Accumulator for R81.10](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.10/Default.htm) starting from Take 93
- [Jumbo Hotfix Accumulator for R81](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81/Default.htm) starting from Take 82
- [Jumbo Hotfix Accumulator for R80.40](https://sc1.checkpoint.com/documents/Jumbo_HFA/R80.40/Default.htm) starting from Take 196

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).

#### NOTE

This solution has been verified for the specific scenario, described by the combination of Product, Version and Symptoms. It may not work in other scenarios.

## Article Properties
**Access Level:** General  
**Status:** Approved by TAC  
**Date Created:** 2022-11-20  
**Last Modified:** 2023-03-22