How to configure jumbo frames on Scaleway Dedibox RPN

Reviewed on March 03, 2025

The RPN network supports by default jumbo frames. This allows you to configure your network interfaces with an MTU 9000 (Maximum transfer unit).

This technology allows you to significantly minimize the interruptions and processor latencies needed for data transfer. The performance gain can reach up to +20% on resource-intensive applications such as iSCSI, NFS, and DRDB.

How to check your current MTU settings

To check your current MTU settings, type:
```
ifconfig ethX | grep MTU
```
Tip
Replace ethX with the name of your RPN interface.
An output like the following example displays:
```
root@my-dedibox-server:~# ifconfig ethX | grep MTU
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
```
In the example above you can see the current MTU of the network interface is set to the Ethernet standard of 1500.

How to set the MTU 9000

On Linux

CentOS

Open the file /etc/sysconfig/network-scripts/ifcfg-ethX, where X is the number of your interface, in a text editor. Then add the following line to it:
```
MTU="9000"
```
Restart the network service:
```
service network restart
```

Debian

Open the file /etc/network/interfaces in a text editor and insert mtu 9000 below the line iface ethX inet static:
```
auto ethX
iface ethX inet static
mtu 9000
[...]
```
Restart the network service:
```
service network restart
```

Ubuntu

Open the Netplan configuration file /etc/netplan/01-netcfg.yaml in a text editor and add the line mtu: 9000 in the configuration of the RPN interface:

ethernets:
    enp3s0:
        dhcp4: true
    enp4s0:
        addresses:
            - 192.168.0.10/24
        gateway4: 192.168.0.1
        mtu: 9000
        nameservers:
            addresses:
                - 1.1.1.1
                - 2.2.2.2

Save the file, exit the text editor, and reload the network configuration:
```
sudo netplan apply
```

On Windows

To change the MTU settings on Windows, you can use a tool like TCP Optimizer to modify the MTU settings.

Download and start the tool.
In the bottom right corner, click Custom.
Go to Network adapter selection and select the RPN interface.
Set the MTU value to 9000.
Click on Apply change to update the MTU settings.