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Device Auxiliary NIC Settings / Backing up over a Secondary NIC


1. Scope

This article shows you how and why to use the auxiliary NICs of a Datto device. For more information about device networking requirements, see the article Datto Networking Requirements. To learn more about the networking user interface, see the article Network Configuration User Interface.

2. Accessing Networking

To get to the Networking Status of a device, go to Remote Web, and click on the Configure tab. Then, click Networking, as shown in Figure 1.

Figure 1 - Configure Networking

3. Usage of Auxiliary NICs

For auxiliary NICs, the best practice is to connect only the NICs intended for active use. Do not enable NICs with no network connected. You may have networking problems if you enable and configure it in Remote Web but don't physically connect it to the network.

Auxiliary NICs are used for the following operations:

  • NIC Teaming 
  • Protection of machines on a separate subnet with no route in place.
  • Separate NIC for a virtual machine hosted on the Datto.
  • Allowing the device to use the primary NIC to check in and perform offsite operations, while performing local backup operations over the secondary NIC.

Things to consider for Auxiliary NIC Configuration

  1. Unless these NICs are physically connected to the network, leave them disabled.
  1. When configuring eth1, eth2, or eth3 to protect a machine on a separate subnet, set the gateway to a live gateway may cause networking problems on your LAN.
  1. For Bare Metal Restores over the network, connect one of the auxiliary NICs with the IP Address, Netmask, & Gateway set to and the mode set to disabled.
    Currently, Hyper-V hypervisor virtualizations cannot use the auxiliary NIC for their offload method. Hyper-V virtualizations must use the primary NIC. 

4. NIC Bonding

  1. In the Network tab of your Datto appliance, select the two NICs to be bonded together, and click Apply Bond Settings.

Figure 2 - Bonded Interfaces settings

5. Protection of machines on a separate subnet

If a Datto device needs to communicate across multiple subnets to protect various machines, you can configure it to do so with the use of the auxiliary NICs. In some situations, you might find this easier than setting up a static route.
  1. First, plug in a live network cable from the other subnet into one of the auxiliary NICs on the Datto.
  2. Then configure the NIC on the Datto device's local web console under the Network tab for an IP and Netmask.
Tip: To avoid routing problems, enter for a gateway for all auxiliary NICs. 
Note: A gateway configured with will not allow traffic out and will leave the primary NIC responsible for outbound communications, which is necessary for proper validation with monitoring servers.
Figure 3 - IP Settings for primary and secondary NICs

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