# Add loopback IP addresses to Virtual Engines

You can use Loopback IP addresses to assign IP addresses that do not belong to any directly connected networks to the Virtual Engine.

##

Loopback IP addresses are not connected to any physical interface and they do not create connectivity to any network.

- Any IP address that is not used to route traffic on another interface can be used as a loopback IP address, and you can add several loopback IP addresses to each Engine.
- The same IP address can be used as a loopback IP address and as the IP address of a Tunnel Interface.
- Loopback IP addresses can be used as the IPv4 Identity for Authentication Requests or IPv6 Identity for Authentication Requests, the IPv4 Source for Authentication Requests or IPv6 Source for Authentication Requests, and the Default IP Address for Outgoing Traffic.

For more details about the product and how to configure features, click Help or press F1.

## Steps

1. Right-click a Security Engine, then select Edit <element type>.
2. Browse to Interfaces > Loopback.
3. Configure the settings.
4. Continue the configuration in one of the following ways:
   - If you are configuring a new Virtual Engine, click Save, close the Engine Editor, then add routes for the Master Engine.
   - Otherwise, click Save and Refresh.

## Engine Editor > Interfaces > Loopback

Use this branch to define loopback IP addresses for Engines. Loopback IP addresses allow you to assign IP addresses that do not belong to any directly connected networks to the Engine.

Option | Definition
--- | ---
Bypass Default IP Address | Specifies how the source IP address for traffic sent from the Security Engine node is selected for tunnel interfaces that do not have IP addresses. Use Loopback IP Address in Unnumbered Tunnel Interface — Uses an IP address listed in the table as the source IP address of traffic sent from the Security Engine node. Use Default Outgoing IP Address in Unnumbered Tunnel Interface — Uses the default outgoing IP address defined in the Interface Options pane as the source IP address of traffic sent from the Security Engine node.
Loopback addresses table | Click Add Row to add a row to the table, or Remove Row to remove the selected row. Click Up or Down to move the selected item up or down.
Loopback Address | Enter the loopback IP address.
CVI Address (Clusters only) | Enter the loopback IP address for the cluster.
Node NDI Address (Clusters only) | Enter the node-specific loopback IP address.
OSPFv2 Area | To advertise the loopback IP address as an OSPFv2 internal route, double-click the cell, then select an OSPFv2 Area element.
Comment (Optional) | A comment for your own reference.