To configure a loopback interface for an Edge:

Prerequisites

For information about the rules and notes that you must consider before you configure a loopback interface, see Loopback Interfaces—Limitations.

Procedure

  1. Log in to VMware SD-WAN Orchestrator, and then go to Configure > Edges.
  2. Either click the Device icon next to the Edge for which you want to configure the loopback interface or click the Edge link, and then go to the Device tab.
  3. Scroll down to the Configure Loopback Interfaces area, and then click Add Loopback.
  4. In the Add Loopback modal popup, configure the required loopback settings. For details, refer to Loopback Interfaces—Field References.
  5. Click Add Loopback.
  6. Click Save Changes.

Results

The loopback interface is listed in the Configure Loopback Interfaces area.

At any point in time, you can choose to edit the loopback interface settings, except CIDR Prefix and Interface ID.

If you delete a loopback interface, the Source Interface field for all the services for which you have selected the loopback interface, is reset to Auto.

In addition, following are two more scenarios based on which the Source Interface for the various services is reset to Auto:
  • If the loopback interface ID is not found in the Edge.
  • If you use older versions of APIs to configure the Edge, sometimes the Edge may not receive the key for source IP address for the services.
When the Source Interface field for any service is set to Auto, the Edge selects the source interface based on the following criteria:
  • Any non-WAN interface that is advertised is prioritized.
  • Among the non-WAN interfaces that are advertised, the source interface selection is based on the following order of priority—Loopback interfaces, VLAN interfaces, or any routed interfaces.
  • If there are more than one interfaces of the same type configured and advertised, the interface with the lowest interface ID is selected.

    For example, if you have two loopback interfaces (LO3 and LO4), one VLAN interface (VLAN2), and two routed interfaces (GE1 and GE2) configured and advertised, and if the Source Interface field for any service is set to Auto, the Edge selects LO3 as the source interface.

What to do next

Once you configure the loopback interface for an Edge, you can select the interface as the source interface for the following services:
Services/Settings For details, refer to ...
Orchestrator Management Traffic Configure Orchestrator Management Traffic for Edges
Authentication Settings Configure Authentication Settings
DNS Settings Configure DNS Settings
Netflow Settings Configure Netflow Settings for Edges
Syslog Settings Configure Syslog Settings for Edges
BGP Settings Configure BGP from Edge to Underlay Neighbors
NTP Settings Configure NTP Settings for Edges
Note:

When the Edge transmits the traffic, the packet header will have the IP address of the selected source interface, whereas the packets can be sent through any interface based on the destination route.