# Mapped IP Address Configuration

Once you configure the mapped IP, you must define an access policy to allow traffic to access the mapped IP address. No address book entry is required for a Mapped IP. The Mapped IP address automatically appears in the drop-down list for the Source Address in the Policy Configuration page.

Note: A mapped IP is required for traffic from the Untrust zone to reach a zone whose interface is in NAT mode. A MIP is optional for traffic from zones other than the Untrust zone to reach a zone whose interface is in NAT mode. Generally, you reference actual host addresses in a policy, but you can also use a MIP to preserve the privacy of addresses in the destination zone.

At the top of the Interface MIP configuration page, you can see for which interface you are configuring a new mapped IP. For example, you see:

Interface: ethernet3/2 (IP/Netmask: 209.122.17.1/24)

### To Configure a MIP

1. On the Interface (MIP) Page, click New, and then enter the necessary information:

Mapped IP: Enter the public IP address which receives inbound traffic that is then redirected to a host with a private IP address.

Note: A MIP must be in the same subnet as the tunnel interface to which it is linked; however, for an interface in the Untrust zone, a MIP does not need to be in the same subnet. In either case, a MIP address must not be the same as the interface address or be in any DIP pool that may also be on that subnet.

Netmask: Enter the subnet mask of the public IP address.

Host IP Address: Enter the private IP address of the host to receive traffic mapped from the public IP address.

Host Virtual Router Name: Select the name of the virtual router to which the host with the private IP address belongs.

2. Click OK to save the settings.