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Setting Up Link Aggregations

  3 minute read.

Last Modified 2022-05-13 13:10 EDT

A Link Aggregation (LAGG) is a general method of combining (aggregating) multiple network connections in parallel or a series to provide additional bandwidth or redundancy for critical networking situations. TrueNAS uses lagg(4) to manage LAGGs.

To set up a LAGG interface, go to Network > Interface > Add.


Set the Type to Link Aggregation.

Enter a name for the interface. The name must use the format laggX, where X is a number representing a non-parent interface. It is also recommended to add any notes or reminders about this particular LAGG in the Description.

Under LAGG Settings, set the Lagg Protocol to configure the interface ports to match your networking needs:

The most commonly used LAGG protocol and is one part of IEEE specification 802.3ad. In LACP mode, negotiation is performed with the network switch to form a group of ports that are all active at the same time. The network switch must support LACP for this option to function.
Failover causes traffic to be sent through the primary interface of the group. If the primary interface fails, traffic diverts to the next available interface in the LAGG.
Load Balance accepts inbound traffic on any port of the LAGG group and then balances the outgoing traffic on the active ports in the LAGG group. It is a static setup that does not monitor the link state nor does it negotiate with the switch.
Round robin accepts inbound traffic on any port of the LAGG group and sends outbound traffic using a round robin scheduling algorithm. Traffic is sent out in sequence using each LAGG interface in turn.
This mode disables traffic on the LAGG interface without disabling the LAGG interface.

Now define the Lagg Interfaces and review the remaining interface options.

See Interfaces Screen for more information on settings.

Other Settings

Every kind of network interface has common settings:


Disabling Hardware Offloading is discouraged as it can reduce network performance. However, disabling this option might be needed when the interface is managing jails, plugins, or virtual machines.

The maximum transmission unit (MTU) is the largest protocol data unit that can be communicated. What the largest workable MTU size can be changes according to your available network interfaces and other physical hardware. 1500 and 9000 are standard Ethernet MTU sizes and the recommendation is to use the default 1500. The permissible range of MTU values is 1492-9216. Leaving this field blank sets the default value of 1500.

If additional tuning is needed, you can enter additional ifconfig settings in the Options.

IP Addresses

Additional aliases for the interface can also be defined:


Either IPv4 or IPv6 addresses and subnets from 1-32 can be defined. Clicking Add provides another field for defining an IP address.

Additional Information

Managing Jails

Managing Plugins

Creating Basic Virtual Machines