# Notice & Limitation

### Default MTU

The default MTU of Pfsense is 1500. You need to adjust this parameter to match the GreenNode configuration of 1450.

**Step 1: Access the pfSense management interface, select the "Interfaces" tab, and configure the WAN (or LAN in use) network one by one.**

<figure><img src="https://1985221522-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F7rE7M1L7GYcwQzNGd0aB%2Fuploads%2Fgit-blob-5da3c0c103d42370c714abedafc0d23b5da0ab95%2Fimage.png?alt=media" alt=""><figcaption></figcaption></figure>

**Step 2: In the MTU section, enter the value 1450.**

Finally, click "Save" to save the configuration.

Repeat these steps for all Interfaces in use.

If you encounter any difficulties during the process, please contact GreenNode support.