Overview

This guide provides step-by-step instructions on how to configure the Dynamic Host Configuration Protocol (DHCP) server settings for a Local Area Network (LAN) interface on a Robustel router running RobustOS. This is useful when you need to define or change the range of IP addresses (IP Pool) that the router assigns to devices connected to its LAN ports, which can help in organizing your network or avoiding IP address conflicts with other equipment.

What You'll Need

• Hardware List:

• 1 x Robustel router (e.g., R1520, R2110, etc.)
• 1 x PC or Laptop with an Ethernet port
• 1 x Standard Ethernet Cable
• 1 x Power Supply for the router

• Software/Firmware:

• A device running a standard version of RobustOS.

• Other Notes:

• Ensure you have the login credentials (username and password) for the router's web interface. The default is admin/admin.

Step-by-Step Configuration Guide

Configure the LAN DHCPv4 Scope

The entire configuration is done within the LAN interface settings. You will navigate to the LAN page, edit the desired interface, and set the gateway IP and DHCP pool parameters.

1. Navigate to the Interface -> LAN menu.
2. Click on the LAN tab.
3. In the Network Settings section, locate the LAN interface you wish to modify (e.g., lan0) and click the edit icon on the right.
4. A configuration window will pop up. Configure the following settings:

1. General Settings: Set the router's IP address and subnet mask. This IP will serve as the default gateway for all devices on this LAN.

• IPv4 Address: Enter the desired gateway IP (e.g., 192.168.1.1).
• Netmask: Enter the corresponding subnet mask (e.g., 255.255.255.0).

2. DHCPv4 Settings: Configure the IP address pool.

• Ensure Enable is toggled to ON.
• Set Mode to Server.
• IP Pool Start: Enter the starting IP address of the DHCP range (e.g., 192.168.1.2).
• IP Pool End: Enter the ending IP address of the DHCP range (e.g., 192.168.1.100).
• Subnet Mask: Enter the subnet mask for the DHCP clients. This typically matches the gateway's mask.

5. Click Submit at the bottom of the pop-up window to save the changes for this interface.
6. Click Save & Apply at the top right of the main page to apply all pending changes to the router's configuration.
   

Verification & Testing

To verify that the DHCP scope has been successfully modified, connect a PC to the router's LAN port and check if it receives an IP address from the newly configured range.

1. Connect Your PC: Connect your computer to one of the LAN ports of the Robustel router using an Ethernet cable.
2. Set PC to DHCP Mode: Ensure your computer's network adapter is configured to "Obtain an IP address automatically".
3. Check DHCP Lease Table: On the router's web interface, navigate to Interface -> LAN and click on the Status tab. In the DHCP Lease Table, you should see your connected PC listed with an IP address that falls within the new scope you defined (e.g., between 192.168.1.2 and 192.168.1.100).
   

Troubleshooting / FAQ

• Q: My computer is not getting an IP address after I applied the changes.

• A:

1. Check Physical Connection: Ensure the Ethernet cable is securely connected to both the router's LAN port and your PC.
2. Verify PC Settings: Double-check that your PC's network adapter is set to obtain an IP address automatically (DHCP mode).
3. Confirm DHCP is Enabled: Navigate back to Interface -> LAN, edit your LAN interface, and confirm that the Enable toggle under DHCPv4 Settings is ON.
4. Reboot: Try rebooting both the router and your computer.

• Q: I lost connection to the router's web interface after clicking "Save & Apply".

• A: This is expected if your computer's IP address is no longer on the same subnet as the router's new IP address. For example, if you changed the gateway IP from 192.168.0.1 to 10.10.0.1, your PC's old 192.168.0.x address can no longer communicate with it.

• Solution: Disconnect and reconnect the Ethernet cable to your PC, or disable and re-enable your network adapter. This will force your PC to request a new IP address from the router's new DHCP scope. You can then access the web interface using the new gateway IP address you configured.

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