LAN port with IP passthrough

Goal

To set up a device attached to the LAN Ethernet port to receive the passthrough IP address of the Digi device's wired WAN or cellular modem connection(s).

Applicable DAL devices

• Digi Enterprise routers
• Digi IX-series Industrial routers
• Digi Connect IT console servers
• Digi AnywhereUSB+

Setup

For this example, you need a DAL device:

• with a wired WAN Internet connection, a cellular modem Internet connection, or both
• running firmware version 19.8.1.15 or higher

Sample

The following diagram shows a sample setup of a Digi 6300-CX with its LAN port 1 set up to provide the IP address of the cellular modem connection as a passthrough to the client device connected to the 6300-CX's LAN port.

Sample configuration

Open the configuration profile for the DAL device, open the Network->Interfaces->LAN section, and make the following changes:

1. Check the Enabled box
2. Change the Interface type to IP Passthrough
3. If the Device option is set to a bridge, click the drop-down and change the setting to a specific LAN Ethernet port that the client device will be connected to in order to receive the passthrough IP. When passthrough mode is enabled for an interface, it will only provide one DHCP IP address to the client device connected to that port. This means only one client device can be connected to the LAN port of the DAL device at a time, because it will only have one passthrough IP to provide at any given point.
4. Under Source Interfaces, click the Add button to create an entry for Internet interface(s) you want to enable passthrough on.  Typically this will be the Modem interface, but additional interfaces (such as the WAN interface) could be included.
5. Save and apply the new configuration settings to the device.

The below example configuration would setup the DAL device in dual-passthrough mode. In this setup, the DAL device will provide its wired WAN IP address as a passthrough IP to the single client device connected to its LAN port, as long as the wired WAN connection is up. The client device will receive this passthrough IP via DHCP. If the wired WAN connection goes down, the DAL device will automatically switch to its cellular modem connection, and automatically trigger a DHCP renewal on the client device so it updates from the WAN passthrough IP to the cellular passthrough IP. The ordering of passthrough interface priority can be arranged through the Network->Interfaces->LAN->Source interfaces list mentioned in step 4 above.