> Source: [sk170533](https://support.checkpoint.com/results/sk/sk170533)

# sk170533 - "Failed to set MTU [XXXX] on interface" error

| Property | Value |
|----------|-------|
| Solution ID | sk170533 |
| Date Created | 2020-11-17 |
| Last Modified | 2020-12-02 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R81 (EOS) |

## Symptoms

- * vsx_util reconfigure fails with: "Failed to set MTU \<high_MTU_size\> on interface"

* Attempt to assign MTU over Clish fails with: ` "NMSETH0029 Failed to set MTU <high_MTU_size> on interface <interface_name>" `

* Similar errors in /var/log/messages:  

  `
  Nov 16 12:13:30 2020 fw xpand[PID]: NETIS Message:Problem occured during MTU setting`  
  `
  Nov 16 12:13:30 2020 fw xpand[PID]: Failed to set MTU 10000 on interface eth3-01`

## Cause

The desired MTU size is higher than maximum supported by the interface driver.

## Solution

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

---

# Agent Instructions

This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products.

## Navigating This Knowledge Base

- **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt)
- **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml)
- **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}`
- **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content