Configuration Example for Policy Based Routing

Consider a typical corporate network scenario where all the branch network traffic passes through a route-based VPN of the corporate network and diverges to the extranet, when required. Accessing the web-based applications that address day-to-day operations through the corporate network results in huge network expansion and maintenance costs. This example illustrates the PBR configuration procedure for direct internet access.

The following figure depicts the topology of a corporate network. The branch network is connected to the corporate network through a route-based VPN. Traditionally, the corporate threat defense is configured to handle both the internal and external traffic of the branch office. With the PBR policy, the branch threat defense is configured with a policy that routes specific traffic to the WAN network instead of the virtual tunnels. The rest of the traffic flows through the route-based VPN, as usual.

This example also illustrates the configuring of the WAN and the VTI interfaces with ECMP zones to achieve load balancing.

Configuring Policy Based Routing on Branch Threat Defense in Management Center
Policy based routing configuration - an example

Before you begin

This example assumes that you have already configured WAN and VTI interfaces for the branch threat defense in management center.

Procedure

Step 1

Configure policy based routing for the branch threat defense, select the ingress interfaces:

  1. Choose Devices > Device Management, and edit the threat defense device.

  2. Choose Routing > Policy Based Routing, and on the Policy Based Routing page, click Add.

  3. In the Add Policy Based Route dialog box, select the interfaces (say, Inside 1, and Inside 2) from the Ingress Interface drop-down list.

Step 2

Specify the match criteria:

  1. Click Add.

  2. To define the match criteria, click the Add (add icon) button.

  3. In New Extended Access List Object, enter the name for the ACL (say, DIA-FTD-Branch), and click Add.

  4. In the Add Extended Access List Entry dialog box, choose the required web-based applications from the Application tab:

    Applications Tab
    Applications tab

    On the threat defense, the application group in an ACL is configured as a network service group and each of the applications as a network service object.

    Extended ACL
    Extended acl for policy based routing

  5. Click Save.

  6. Select DIA-FTD-Branch from the Match ACL drop-down list.

Step 3

Specify the egress interfaces:

  1. From the Send To and Interface Ordering drop-down lists, choose Egress Interfaces, and By Priority respectively.

  2. Under Available Interfaces, click the button against the respective interface names to add WAN1 and WAN2:

    Configuring Policy Based Routing
    pbr

  3. Click Save.

Step 4

Interface priority configuration:

You can set the priority value for the interfaces either in the Edit Physical Interface page, or in the Policy Based Routing page (Configure Interface Priority). In this example, the Edit Physical Interface method is described.

  1. Choose Devices > Device Management, and edit the branch threat defense.

  2. Set the priority for the interfaces. Click Edit against the interface and enter the priority value:

    Setting Interface Priority
    Setting interface priority

  3. Click Ok and Save.

Step 5

Create ECMP zones for load balancing:

  1. In the Routing page, click ECMP.

  2. To associate interfaces to the ECMP zone, click Add.

  3. Select WAN1 and WAN 2 and create an ECMP zone—ECMP-WAN. Similarly, add VTI01 and VTI02 and create an ECMP zone—ECMP-VTI:

    Associating Interfaces with ECMP Zone
    ECMP zone and interfaces

Step 6

Configure static routes for the zone interfaces for load balancing:

  1. In the Routing page, click Static Route.

  2. Click Add and specify the static routes for WAN1, WAN2, VTI01, and VTI02. Ensure that you specify the same metric value for the interfaces belonging to the same ECMP zones (Step 5):

    Configuring Static Routes for ECMP Zone Interfaces
    Configuring static routes - ECMP zones
    Note

    Ensure that the zone interfaces have the same destination address and metric, but different gateway addresses.

Step 7

Configure trusted DNS on the WAN objects of the branch threat defense to ensure secured flow of traffic to the internet:

  1. Choose Devices > Platform Settings, and create a DNS policy on the branch threat defense.

  2. To specify the trusted DNS, Edit the policy and click DNS.

  3. To specify the DNS servers for the DNS resolution to be used by WAN objects, in the DNS Settings tab, provide the DNS server group details and select WAN from the interface objects.

  4. Use the Trusted DNS Servers tab to provide specific DNS servers that you trust for the DNS resolution.

Step 8

Save and Deploy.

Any YouTube related access requests from the branch inside network INSIDE1 or INSIDE2 are routed to WAN1 or WAN2 as they would match the DIA-FTD-Branch ACL. Any other request, say google.com, are routed through VTI01 or VTI02 as configured in the Site to Site VPN Settings:

Site to Site VPN Settings
Example s2s vpn

With the ECMP configured, the network traffic is seamlessly balanced.