How To Configure Firewall Segmentation

NetScaler SD-WAN 9.2 introduces VRF firewall segmentation to give multiple routing domains access to the internet through a common interface, with each domain’s traffic isolated from that of the others. For example, employees and guests can access the internet through the same interface, without any access to each other’s traffic.

  • Local guest-user Internet access
  • Employee-user Internet access for defined applications
  • Employee-users may continue hairpin all other traffic to the MCN
  • Allow the user to add specific routes for specific routing domains.
  • When enabled, this feature applies to all routing domains.

You can also create multiple access interfaces to accommodate separate public facing IP addresses. Either option provides the required security necessary for each user group.


For more information, see how to configure VRFs.

To configure internet services for all Routing Domains:

  1. Create Internet Service for a Site. Navigate to Connections > [Site Name] > Internet Services and and, under WAN Links, select the Use check box.

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  2. Navigate to Sites > [Site Name] > WAN Links > [WAN Link Name] > Access Interfaces and select the **Internet Access for All Routing Domains **check box.

    Selecting this check box allows SD-WAN to use this access interface for internet service on all configured routing domains. The check box is grayed out if two or more access interfaces are configured for the same WAN link. You can configure either a shared access interface or one access interface for each group (separate public-facing IP addresses).

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    After completing the following steps you should see routes added, one per routing domain, under Connections > [Site Name] > **Routes. **

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    It is no longer required to have all routing domains enabled at the MCN.

    If you disable routing domains at the MCN, the following message appears if the domains are in use at a branch site:

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    You can confirm that each routing domain is using the internet service by checking the Routing Domain column in the Flows table of the web management interface under Monitor > Flows.

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    You can also check the routing table for each routing domain under Monitor > Statistics > Routes.

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Use Cases

In previous NetScaler SD-WAN releases, virtual routing and forwarding have the following issues:

  • Customers have multiple routing domains at a branch site without the requirement to include all domains at the data center (MCN). They need the ability to isolate different customers’ traffic in a secure manner
  • Customers must be able to have a single accessible firewalled Public IP address for multiple routing domains to access the internet at a site (extend beyond VRF lite).
  • Customers need an Internet route for each routing domain supporting different services

Release 9.2 introduces the following enhancements to address the above concerns.

  • Multiple routing domains at a branch site
  • Internet Access for different routing domains

Multiple routing domains at a branch site

With the Virtual Forwarding and Routing Firewall segmentation enhancements, you can:

  • Provide an infrastructure, at the branch site, that supports secure connectivity for at least two user groups, such as employees and guests. The infrastructure can support up to 16 routing domains.
  • Isolate each routing domain’s traffic from the the traffic of any other routing domain.
  • Provide internet access for each routing domain,

  • A common Access Interface is required and acceptable

  • An Access Interface for each group with separate Public facing IP addresses

  • Traffic for the employee can be routed directly out to the local internet (specific applications)
  • Traffic for the employee can be routed or backhauled to the MCN for extensive filtering (0 route)
  • Traffic for the routing domain can be routed directly out to the local internet (0 route)
  • Supports specific routes per routing domain, if required
  • Routing domains are VLAN based
  • Removes the requirement for the RD to have to reside at the MCN
  • Routing Domain can now be configured at a branch site only
  • Allows you to assign multiple RD to an access interface (once enabled)
  • Each RD will be assigned a route
  • Allows specific routes to be added for a RD
  • Allows traffic from different RD to exit to the internet using the same access interface
  • Allows you to configure a different access interface for each RD
  • Must be unique subnets (RD are assigned to a VLAN)
  • Each RD can use the same FW default Zone
  • The traffic is isolated through the Routing Domain
  • Outbound flows have the RD as a component of the flow header. Allows SD-WAN to map return flows to correct Routing domain.

Prerequisites to configure multiple routing domains:

  • Internet access is configured and assigned to a WAN Link.
  • Firewall configured for NAT and correct policies applied.
  • Second routing domain added globally.
  • Each routing domain added to a site.
  • At Sites > Site Name > WAN Links > WL2 [name] > Access Interface, make sure that the check box is available and internet service has been defined correctly. If you cannot select the check box, the internet service is not defined or assigned to a WAN link for the site.

Deployment Scenarios

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  • The internet service must be added to the WAN link before you can enable Internet access for all Routing Domains. (Until you do, the check box for enabling this option is grayed out).

    After enabling internet access for all routing domains, auto add a dynamic-NAT rule.

  • Up to 16 Routing Domains per site.
  • Access Interface (AI): Single AI per subnet.

  • Multiple AIs require a separate VLAN for each AI.

  • If you have two routing domains at a site and have a single WAN Link, both domains use the same public IP address.

  • If Internet access for all routing domains is enabled, all sites can route to Internet. (If one routing domain does not require internet access, you can use the firewall to block its traffic.)
  • No support for the same subnet in multiple routing domains.

  • There is no audit functionality

  • The WAN links are shared for Internet access.
  • No QOS per routing domain; first come first serve.