TrueNAS SCALE Version Documentation
This content follows the TrueNAS SCALE 24.04 (Dragonfish) releases. Use the Product and Version selectors above to view content specific to different TrueNAS software or major version.

Managing Interfaces

5 minute read.

Last Modified 2025-04-25 15:21 EDT

The Network screen allows you to add new or edit existing network interfaces, and configure static and alias IP addresses.

Why should I use different interface types?

Use LAGG (Link Aggregation) to optimize multi-user performance, balance network traffic, or have network failover protection.

For example, failover LAGG prevents a network outage by dynamically reassigning traffic to another interface when one physical link (a cable or NIC) fails.

Use a network bridge to enable communication between two networks and provide a way for them to work as a single network.

For example, bridges can serve IPs to multiple VMs on one interface, which allows your VMs to be on the same network as the host.

Prepare your system for interface changes by stopping and/or removing apps, VM NIC devices, and services that can cause conflicts:

Stop running apps before proceeding with network interface changes.
Power off any running virtual machines (VMs) before making interface IP changes. Remove active NIC devices.

If you encounter issues with testing network changes, you might need to stop any services, including Kubernetes and sharing services such as SMB, using the current IP address.

One Static IP Address or Multiple Aliases?

One or More Aliases?

Static IP addresses set a fixed address for an interface that external devices or websites need to access or remember, such as for VPN access.

Use aliases to add multiple internal IP addresses, representing containers or applications hosted in a VM, to an existing network interface without having to define a separate network interface.

In the UI, you can add aliases when adding or editing an existing interface using the Add button to the right of the Aliases. To add a static IP. Click Add again to add an additional alias.

From the Console Setup menu, select option 1 to configure network settings and add alias IP addresses.

Adding an Interface

You can use DHCP to provide the IP address for only one network interface and this is most likely for your primary network interface configured during the installation process.
To add another network interface, click Add on the Interfaces widget to display the Add Interface panel. Leave the DHCP checkbox clear. Click Add to the right of Aliases, near the bottom of the Add Interface screen and enter a static IP address for the interface.

You must specify the type of interface you want to create. Select the type of interface from the Type dropdown options: Bridge, Link Aggregation or LAGG, and VLAN or virtual LAN. You cannot edit the interface type after you click Save.

Each interface type displays new fields on the Add Interface panel. Links with more information on adding these specific types of interfaces are at the bottom of this article.

Editing an Interface

Click on an existing interface in the Interfaces widget then click on the Edit icon to open the Edit Interface screen. The Edit Interface and Add Interface settings are identical except for Type and Name. You cannot edit these settings after you click Save. Name shows on the Edit Interface screen, but you cannot change the name. Type only shows on the Add Interface screen. If you make a mistake with either field you can only delete the interface and create a new one with the desired type.

If you want to change from DHCP to a static IP, you must also add the new default gateway and DNS nameservers that work with the new IP address. See Setting Up a Static IP for more information.

If you delete the primary network interface you can lose your TrueNAS connection and the ability to communicate with the TrueNAS through the web interface!
You might need command line knowledge or physical access to the TrueNAS system to fix misconfigured network settings.

Deleting an Interface

Click the icon for the interface. A delete interface confirmation dialog opens.

Do not delete the primary network interface!
If you delete the primary network interface you lose your TrueNAS connection and the ability to communicate with the TrueNAS through the web interface! You might need command line knowledge or physical access to the TrueNAS system to fix misconfigured network settings.

Adding Alias IP Addresses

Multiple interfaces connected to a single TrueNAS system cannot be members of the same subnet.
You can combine multiple interfaces with link aggregation (LAGG) or a network bridge. Alternatively, you can assign multiple static IP addresses to a single interface by configuring aliases.
Click for more information
When multiple network interface cards (NICs) connect to the same subnet, users might incorrectly assume that the interfaces automatically load balance. However, ethernet network topology allows only one interface to communicate at a time. Additionally, both interfaces must handle broadcast messages since they are listening on the same network. This configuration adds complexity and significantly reduces network throughput.
If you require multiple NICs on a single network for performance optimization, you can use a link aggregation (LAGG) configured with Link Aggregation Control Protocol (LACP). A single LAGG interface with multiple NICs appears as a single connection to the network.
While LACP is beneficial for larger deployments with many active clients, it might not be practical for smaller setups. It provides additional bandwidth or redundancy for critical networking situations. However LACP has limitations as it does not load balance packets.
On the other hand, if you need multiple IP addresses on a single subnet, you can configure one or more static IP aliases for a single NIC.
In summary, we recommend using LACP if you need multiple interfaces on a network. If you need multiple IP addresses, define aliases. Deviation from these practices might result in unexpected behavior.
For a detailed explanation of ethernet networking concepts and best practices for networking multiple NICs, refer to this discussion from National Instruments.

To configure alias IPs to provide access to internal portions of the network, go to the Network screen:

Click on the Edit icon for the interface to open the Edit Interface screen for the selected interface.
Figure 1: Add Alias
Clear the DHCP checkbox to show Aliases. Click Add for each alias you want to add to this interface.
Enter the IP address and CIDR values for the alias(es).
Select DHCP to control the primary IP for the interface.
Click Save.

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Resources

Managing Interfaces

One Static IP Address or Multiple Aliases?

Adding an Interface

Editing an Interface

Deleting an Interface

Adding Alias IP Addresses

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