Advanced Routing Services

For appliances running SonicOS versions 5.6 and higher, VPN Tunnel Interfaces can be configured for advanced routing. To do so, you must enable advanced routing for the tunnel interface on the Advanced tab of its configuration. See Generic VPN Configuration in SonicOS Enhanced for more information.

After you have enabled advanced routing for a Tunnel Interface, it is displayed in the list with the other interfaces in the Advanced Routing table on the Network > RIP (ENH) page.

The RIP configurations for Tunnel Interfaces are very similar to the configurations for traditional interfaces with the addition of two new options that are listed at the bottom of the RIP configuration window under a new Global Unnumbered Configuration heading.

When running SonicOS version 5.9 or higher, a BGP drop-down menu is available under the Advanced Routing Services heading. This menu gives you the options to enable or disable the BGP feature and is only available if Use Advanced Routing is clicked.

Global Unnumbered Configuration

Because Tunnel Interfaces are not physical interfaces and have no inherent IP address, they must “borrow” the IP address of another interface. Therefore, the advanced routing configuration for a Tunnel Interface includes the following options for specifying the source and destination IP addresses for the tunnel:

•	IP Address Borrowed From - The interface whose IP address is used as the source IP address for the Tunnel Interface.

NOTE: The borrowed IP address must be a static IP address.

•	Remote IP Address - The IP address of the remote peer to which the Tunnel Interface is connected. In the case of a SonicWALL-to-SonicWALL configuration with another Tunnel Interface, this should be the IP address of the borrowed interface of the Tunnel Interface on the remote peer.

 

NOTE: The IP Address Borrowed From and Remote IP Address values apply to both RIP for the Tunnel Interface.

Guidelines for Configuring Tunnel Interfaces for Advanced Routing

The following guidelines ensure success when configuring Tunnel Interfaces for advanced routing:

•	The borrowed interface must have a static IP address assignment.

•	The borrowed interface cannot have RIP enabled on its configuration.

TIP: SonicWALL recommends creating a VLAN interface that is dedicated solely for use as the borrowed interface. This avoids conflicts when using wired connected interfaces.

•	The IP address of the borrowed interface should be from a private address space, and should have a unique IP address in respect to any remote Tunnel Interface endpoints.

•	The Remote IP Address of the endpoint of the Tunnel Interface should be in the same network subnet as the borrowed interface.

•	The same borrowed interface might be used for multiple Tunnel Interfaces, provided that the Tunnel interfaces are all connected to different remote devices.

•	When more than one Tunnel Interface on an appliance is connected to the same remote device, each Tunnel Interface must use a unique borrowed interface.

Depending on the specific circumstances of your network configuration, these guidelines might not be essential to ensure that the Tunnel Interface functions properly. But these guidelines are SonicWALL best practices that will avoid potential network connectivity issues.