# Define contact addresses for Security Engines

You must define a Location and a contact address if NAT is applied to the communications between the Security Engine and some other component that contacts the Security Engine.

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If you use Multi-Link, add contact addresses for each NetLink.

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

## Steps

1. Select Engine.
2. Right-click an engine element and select Edit <element type>.
   The Engine Editor opens.
3. In the General pane, select the Location for this element.
4. Browse to Interfaces in the navigation pane on the left.
5. In the tree view, expand the tree and double-click the Cluster Virtual IP Address (CVI), Node Dedicated IP Address (NDI), or the IP address for which you want to define a contact address.
   On Engine Clusters, the CVI contact address is used for VPNs and NDI contact addresses are used for other system communications.