Use a PBF rule to direct traffic to a specific egress interface on the firewall, and override the default path for the traffic.
Create a PBF Rule
Create a PBF rule. When creating a PBF rule you must specify a name for the rule, a source zone or interface, and an egress interface. All other components are either optional or have a default value provided. You can specify the source and destination addresses using an IP address, an address object, or a FQDN. For the next hop, however, you must specify an IP address. Select Policies > Policy Based Forwarding and click Add. Give the rule a descriptive name in the General tab. In the Source tab, select the following: Select the Type Zone or Interface — to which the forwarding policy will be applied, and the relevant zone or interface. If you want to enforce symmetric return, you must select a source interface. PBF is only supported on Layer 3 interfaces; loopback interfaces do not support PBF. (Optional) Specify the Source Address to which PBF will apply. For example, a specific IP address or subnet IP address from which you want to forward traffic to the interface or zone specified in this rule. Use the Negate option to exclude a one or more source IP addresses from the PBF rule. For example, if your PBF rule directs all traffic from the specified zone to the internet, Negate allows you to exclude internal IP addresses from the PBF rule. (You can also use Negate to exclude destination IP addresses you specify in substep 4.) The evaluation order is top down. A packet is matched against the first rule that meets the defined criteria; after a match is triggered the subsequent rules are not evaluated. (Optional) Add and select the Source User or groups of users to whom the policy applies. In the Destination/Application/Service tab, select the following: Destination Address. By default the rule applies to Any IP address. Use the Negate option to exclude one or more destination IP addresses from the PBF rule. Select the Application(s) or Service(s) that you want to control using PBF. Application-specific rules are not recommended for use with PBF. Whenever possible, use a service object, which is the Layer 4 port (TCP or UDP) used by the protocol or application. For more details, see Service Versus Applications in PBF.
Specify how to forward traffic that matches the rule. If you are configuring PBF in a multi-VSYS environment, you must create separate PBF rules for each virtual system (and create the appropriate Security policy rules to enable the traffic). In the Forwarding tab, select the following: Set the Action. The options are as follows: Forward —Directs the packet to a specific Egress Interface. Enter the Next Hop IP address for the packet (you cannot use a domain name for the next hop). Forward To VSYS —(On a firewall enabled for multiple virtual systems) Select the virtual system to which to forward the packet. Discard —Drop the packet. No PBF —Exclude the packets that match the criteria for source/destination/application/service defined in the rule. Matching packets use the route table instead of PBF; the firewall uses the route table to exclude the matched traffic from the redirected port. To trigger the specified action at a daily, weekly or non-recurring frequency, create and attach a Schedule.(Optional) Enable Monitoring to verify connectivity to a target IP address or to the next hop IP address. Select Monitor and attach a monitoring Profile (default or custom) that specifies the action when the IP address is unreachable. (Optional, required for asymmetric routing environments) Select Enforce Symmetric Return and enter one or more IP addresses in the Next Hop Address List (you cannot use an FQDN as the next hop). You can add up to 8 next-hop IP addresses; tunnel and PPoE interfaces are not available as a next-hop IP address. Enabling symmetric return ensures that return traffic (say, from the Trust zone on the LAN to the internet) is forwarded out through the same interface through which traffic ingresses from the internet.
Save the policies to the running configuration on the firewall. Click Commit. The PBF rule is in effect.

Related Documentation