Fortinet 50A user manual

Virtual IPs Firewall configuration

Adding static NAT virtual IPs

To add a static NAT virtual IP

1Go to Firewall > Virtual IP.

2Select New to add a virtual IP.

3Type a Name for the virtual IP.

The name can contain numbers (0-9), uppercase and lowercase letters (A-Z, a-z), and the special characters - and _. Other special characters and spaces are not allowed.

4Select the virtual IP External Interface from the list.

The external interface is the interface connected to the source network that receives the packets to be forwarded to the destination network.

You can set the virtual IP external interface to any FortiGate interface. Table 19 contains example virtual IP external interface settings and describes the policies that you can add the resulting virtual IP to.

Table 19: Virtual IP External Interface examples

External Interface	Description
internal	To map an internal address to an external address. If you select internal,
	the static NAT virtual IP can be added to Int->Ext policies.
external	To map an external address to an internal address. If you select external,
	the static NAT virtual IP can be added to Ext->Int policies.

5In the Type section, select Static NAT.

6Enter the External IP Address that you want to map to an address on the destination network.

For example, if the virtual IP provides access from the Internet to a web server on a destination network, the external IP address must be a static IP address obtained from your ISP for your web server. This address must be a unique address that is not used by another host and cannot be the same as the IP address of the external interface selected in step 4. However, this address must be routed to this interface. The virtual IP address and the external IP address can be on different subnets.

If the IP address of the external interface selected in step 4 is set using PPPoE or DHCP, you can enter 0.0.0.0 for the external IP address. The FortiGate unit substitutes the IP address set for this external interface using PPPoE or DHCP.

7In Map to IP, type the real IP address on the destination network, for example, the IP address of a web server on an internal network.

Note: The firewall translates the source address of outbound packets from the host with the

Map to IP address to the virtual IP External IP Address, instead of the firewall external address.

8Select OK to save the virtual IP.

You can now add the virtual IP to firewall policies.

158 Fortinet Inc.