Overview

By default, all Ethernet LAN ports on a Robustel router are bridged together and assigned to a single LAN interface (lan0). This configuration is suitable for simple flat networks. However, for scenarios requiring network segmentation—such as separating office traffic from industrial control traffic or creating a distinct guest network—you need to assign different Ethernet ports to separate LAN interfaces. This guide will walk you through the process of creating a new LAN interface (e.g., lan1) and binding it to a specific physical Ethernet port (e.g., eth1), complete with its own IP subnet and DHCP server.

This configuration is useful when you need to:

• Isolate different types of network traffic for security or performance reasons.
• Create multiple independent subnets using a single router.
• Apply different network policies (like firewall rules) to different physical ports.

What You'll Need

Hardware List:

• 1 x Robustel router with multiple Ethernet ports (e.g., R1520, R2110, R2120, R5020).
• 1 x PC with an Ethernet port.
• 2 x Ethernet cables.

Software/Firmware:

• RobustOS firmware V5.3.5 or newer.

Prerequisites:

• Ensure your PC is connected to the router's LAN port via an Ethernet cable.
• Log in to the Router's web interface. The default IP address is typically http://192.168.0.1.

Step-by-Step Configuration Guide

Step 1: Assign an Ethernet Port to a New LAN Interface

The first step is to unbind a physical Ethernet port from the default lan0 interface and assign it to a new logical interface, which we will call lan1.

1. Navigate to Interface -> Ethernet from the main menu.
2. Click on the Ports tab, Under the Ports Settings section, you will see a list of physical Ethernet ports (eth0, eth1, etc.). By default, they are all assigned to lan0.
3. Click the Edit icon for the Ethernet port you wish to reassign (for this example, we will use eth1).
4. In the pop-up window, find the Port Assignment dropdown menu. Change the selection from lan0 to a new LAN interface. (For this example, we will select lan1. )
5. Click Submit to close the pop-up window.
6. Click Save & Apply at the top of the page to save the changes.
   

Step 2: Configure the New LAN Interface

Now that the chosen Ethernet port (e.g., eth1) is assigned to a new LAN interface (e.g., lan1), you need to configure the network settings for that new interface, including its IP address and DHCP server.

1. Navigate to Interface -> LAN from the main menu.
2. Click on the LAN tab.
3. Under the Network Settings section, click the + (Add) button to create a new LAN interface configuration.
4. A pop-up window will appear. In the General Settings section:

• For Interface, select the new LAN interface you assigned in the previous step (in this example, lan1).
• For IPv4 Address, enter the gateway IP for this new subnet (e.g., 192.168.1.1).
• For Netmask, enter the corresponding subnet mask (e.g., 255.255.255.0).

5. Scroll down to the DHCPv4 Settings section within the same pop-up:

• Set the Enable toggle to ON.
• Ensure the Mode is set to Server.
• For IP Pool Start, enter the beginning of the IP range you want to assign (e.g., 192.168.1.2).
• For IP Pool End, enter the end of the IP range (e.g., 192.168.1.100).
• For Subnet Mask, enter the mask for the DHCP clients (e.g., 255.255.255.0).

6. Click Submit to save the new LAN configuration.
7. Click Save & Apply at the top of the page to apply all changes.
   

Verification & Testing

To confirm the configuration is working correctly, you will connect your PC to the newly configured Ethernet port and verify that it receives an IP address from the new subnet.

1. Connect your PC directly to the Ethernet port you configured in Step 1 (e.g., eth1).
2. Ensure your PC's network adapter is set to "Obtain an IP address automatically" (DHCP).
3. Once connected, your PC should receive an IP address from the range you defined in Step 2 (e.g., an address between 192.168.1.100 and 192.168.1.200).
4. Open a command prompt or terminal on your PC and use the ping command to test connectivity to the new LAN gateway IP.

ping 192.168.1.1

5. If you receive successful replies, the configuration is correct.
   

6. You can also navigate to Interface -> LAN and click the Status tab on the router's web interface. In the DHCP Lease Table, you should see an entry for your PC, showing the IP address it has been assigned.
   

Troubleshooting / FAQ

• Q: My PC is not getting an IP address after connecting to the new port (eth1). What should I do?

• A: First, verify that you have clicked the main Save & Apply button after completing both Step 1 and Step 2. A common mistake is to only click "Submit" in the pop-up windows. Second, double-check in Interface -> Ethernet that eth1 is assigned to lan1. Finally, ensure that the DHCPv4 server is Enabled for the lan1 interface in the Interface -> LAN settings.

• Q: Can I assign more than two LAN interfaces?

• A: Yes, the RobustOS software supports creating lan1. Depending on the device model and firmware, additional interfaces may be supported. You can assign different physical ports to different LAN interfaces (e.g., eth1 to lan1, eth2 to lan2) as needed.

Revision History