> Source: [sk171912](https://support.checkpoint.com/results/sk/sk171912)

# sk171912 - A custom script executed on a Spark Firewall creates VLAN interfaces on the wrong physical interface

| Property | Value |
|----------|-------|
| Solution ID | sk171912 |
| Date Created | 2021-02-20 |
| Last Modified | 2022-07-13 |
| Technical Level | General |
| Products | Spark Firewall (Locally Managed) |
| Versions | R81.10.X |
| Platform | 1500 |

## Symptoms

- * After running a custom configuration script to create VLAN interfaces on SMB appliances with version R80.20.02, the VLAN interfaces were configured on a wrong physical interface.
* The output from running the configuration script shows this error message: "*Failed to find the requested interface*".

## Cause

The SMB appliance selects the first physical interface which is in the "unassigned" state and creates the VLAN tag on that interface.

## Solution

This problem was fixed. The fix is included in:

* **R80.20.05 and higher**

Check Point recommends that you always [upgrade to the most recent version](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk157412).

**Workaround:**

1. Make sure each physical interface has an IP address assigned.

2. Disable the physical interface whose number is lower than the physical interface, on which it is necessary to configure VLAN interfaces.

   For example, if a VLAN tag is required on LAN2:
   1. Configure LAN1 with an IP address.
   2. Run: `set interface LAN1 state off`

The interfaces are checked for the next available interface in this order:

1. WAN
2. DMZ
3. LAN1
4. LANX

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