Product Documentation

Static NAT Configuration

Aug 09, 2017

Static NAT allows the user to configure one-to-one NAT, where an inside IP address will match a public IP address. The configuration options are shown below. You must also define the filter policies to allow traffic back in for the static NAT configuration.

 

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Configuration Options

     *  Priority - the order the policy will be applied within all the defined policies. Lower priority policies are applied before higher priority polices.

     *  Direction – the direction, from the perspective of the virtual interface or service, that the translation will operate.

     *  Outbound – the destination address for a packet will be translated for packets received on the service. The source address will be translated for packets transmitted on the service.

For example, LAN service to Internet service – for packets outbound, (LAN to Internet) the source IP address is translated. For packets inbound or received (Internet to LAN) the destination IP address are translated.

     *  Inbound - the source address for a packet will be translated for packets received on the service. The destination address will be translated for packets transmitted on the service.

For example,  Internet service to LAN service – For packets received on the Internet service, the source IP address is translated. For packets transmitted on the Internet service, the destination IP address is translated.

     *  Service Type – in reference to a SD-WAN service. For static NAT, these include Local (to the appliance), Intranet, and Internet.

     *  Service Name – specific service name that corresponds to the defined Service Type above.

     *  Inside Zone – one of the existing inside zones configured on the appliance.

     *  Inside IP address – source IP address and mask of the direction selected above.

     *  Outside IP address – the outside IP address and mask of packets that are translated to.

Connections can get originated in either inside -> outside (or) outside -> inside directions. When NAT rule is created, it gets applied for both directions. Depending on the NAT rule type (inbound/outbound), the parameters are considered for matching changes.

In the following configuration showin in below figure:

        When connection is initiated from inside to outside, Packet has to match following conditions to get the NAT policy applied:

  1. source service = Local and service name = LAN

  2. source IP address = 192.168.10.9

  3. source firewall zone = FIC (inside zone)

    When connection is initiated from outside to inside, Packet has to match following conditions to get the NAT policy applied:

  1. source firewall zone = Default_LAN_Zone (outside zone)

  2. destination IP address = 10.28.115.81

The directions in NAT type are with respective to SD-WAN appliance.

  • If NAT has to be applied when connection is entering to the appliance then, it is Inbound NAT. In this case, Firewall filters are applied on translated/outside IP addresses.

  • If NAT has to be applied when connection is leaving the appliance then, it is Outbound NAT. In this case, Firewall filters are applied on actual IP addresses.

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Note

After NAT policy is applied destination service name must be LAN, else packet will be dropped.