Configuring the LAN and USB Interfaces

Topics on this page: Connecting via Ethernet and/or USB | Configuring the LAN (Ethernet) Interface | Configuring the USB Interface IP Address

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This topic describes how to configure the interfaces on the ADSL/Ethernet router that communicate with your LAN and USB computers.

Connecting via Ethernet and/or USB

If you are using the ADSL/Ethernet router with multiple PCs on your LAN, you must connect the LAN via an Ethernet hub connected to the device's LAN port. If you are using a single PC with the ADSL/Ethernet router, you have two connection options:

  • You can connect the PC directly to the LAN port using a cross-over Ethernet cable. See your User's Manual for a description of cross-over and straight-through Ethernet cables.
  • If the PC is USB-enabled, you can connect it directly to the device's USB port. Only one computer can be connected in this manner.

You can also use the USB and Ethernet interfaces simultaneously, connecting your LAN to the Ethernet port and a standalone PC to the USB port.

You must assign a unique IP address to each device interface that you use.

Configuring the LAN (Ethernet) Interface

In order to use the device as a router on your LAN, Internet Protocol (IP) properties must be assigned to the LAN interface. These properties must identify the interface as residing in the same subnet as the PCs on your LAN.

Default IP properties are assigned to the LAN interface. You will need to change these properties if the IP properties on your PCs place them in a different subnet.

If the IP addresses that you want to assign to your PCs are not in the same subnet as the default LAN interface, you can use the configuration program to change the LAN interface IP properties accordingly. However, because you must access the program from a PC in the same subnet as the LAN interface, initially configure one PC as indicated in the Quick Start. Then, access the configuration program and change the LAN IP address as required. When done, change the IP properties on the PC to so that it is also in the appropriate subnet.

If your network uses a DHCP server (other than the ADSL/Ethernet router) to assign IP addresses, you can configure the device to accept and use a LAN IP address assigned by that server. Similarly, if your ISP performs DHCP serving for your network, you can configure the device to accept an IP address assigned from the ISP's server. In this mode, the ADSL/Ethernet router is considered a DHCP client of your (or your ISP's) DHCP server.

 

The ADSL/Ethernet router itself can function as a DHCP server for your LAN computers, as described in Configuring DHCP Server, but not for its own LAN interface.

Follow these steps to change the LAN interface IP address or to configure the LAN port as a DHCP client:

  1. If the LAN Configuration page is not already displaying, click the LAN tab in the task bar. The LAN Configuration page displays by default.

Depending on the preconfigured settings, the LAN Configuration or USB Configuration table may not display. You cannot create these interfaces using Configuration Manager. Contact your ISP for assistance.
The LAN Configuration table displays the following settings:
  • System Mode: Identifies the system operating mode for your device, such as Routing mode, Bridging mode, or both modes simultaneously. See Configuring the System Mode for more information). 
  • Get LAN Address: Provides options for how the device's LAN interface is assigned an IP address:
    • Manual indicates that you will be assigning a static IP address, which you can enter in the fields below
    • External DHCP Server indicates that your ISP will be assigning an IP address from their own DHCP server, dynamically each time you log on. 
    • Internal DHCP Server indicates that you have a DHCP server device on your network that will assign an address to the port.

If you choose either the internal or external server option, the LAN interface is called a DHCP client of the server. 

Note that the public IP address assigned to you by your ISP is not your LAN IP address. The public IP address identifies the WAN (ADSL) port on your ADSL/Ethernet router to the Internet. Or, in bridge configurations, it may be assigned to a PC.

  • Speed/Duplex: Speed indicates the speed of the Ethernet communication between the ADSL/Ethernet router and the LAN PCs or hub. Duplex indicates the type of Ethernet communication (i.e., full duplex, or half-duplex). These settings are not user-configurable.
  • LAN IP Address and Network Mask: The IP address and network mask for the port.
  • IGMP: Indicates whether this interface is enabled with the Internet Group Management Protocol. When enabled, the ADSL/Ethernet router collects and consolidates requests from the LAN PCs to receive IGMP messages from external computers. The interface also forwards IGMP messages it receives on its WAN interface to the appropriate hosts. The WAN interface must also be enabled for the IGMP protocol (see the Quick Configuration help topic for more information).
  • MTU: The Maximum Transmission Unit specifies the size in bytes of the largest Ethernet packet that the interface will accept. Packets larger than this size will be dropped.
  1. Enter an IP address and mask in the fields provided and choose Disabled in the Use DHCP field, or enable either a remote or local DHCP server. Keep these points in mind:
  • Manually specifying an address: If you are using routing services on you LAN such as DHCP and NAT, click the Manual setting and assign a fixed LAN IP address and mask to the interface. The IP address you assign must be in the same subnet as your LAN computers that connect to it.

    If you change the LAN IP address, you may need to update the DHCP configuration so that the addresses that the DHCP server dynamically assigns to your computers are on the same subnet as the new LAN IP address. See Configuring DHCP Server for instructions on changing the pool of dynamically assigned addresses.
  • Enabling DHCP: If you choose to have the LAN interface be a DHCP client of an internal or external server, the LAN Network Mask field will be dimmed and made unavailable for entry. The LAN IP Address field will remain editable, however. The address that you specify here will be used as a request to the DHCP server. This is referred to as a "Configured IP Address" in the program. If the configured IP address is not available, then the device will accept another address from the server. Even if another number is assigned, the same configured IP address will continue to display in this field.

    For a description of the DHCP service (as it applies to the device's own DHCP server), see DHCP Configuration Overview.
  1. If you are using IGMP on your network, click the IGMP Enable radio button.
  2. Click Save Changes.
  • If you changed the LAN IP address while working from a PC that is connected to the device via Ethernet, then your connection will be terminated.
  • If you changed the LAN IP address while working from a PC connected to the device via USB, a page will display to confirm your change and your connection will remain active.
  • If you enabled the DHCP service, the ADSL/Ethernet router will initiate a request for an IP address from your LAN's DHCP server. If a different IP address is assigned than was previously configured, your current connection will be terminated.
  1. Reconfigure your PCs, if necessary, so that their IP addresses place them in the same subnet as the new IP address of the LAN interface.
  2. Log into Configuration Manager by typing the new IP address in your Web browser's address/location box.

NOTE: If want your changes to be permanent, be sure to Write Settings to Flash.

Configuring the USB Interface IP Address

The IP address must place the USB interface in the same subnet as the USB computer. The USB interface and USB computer can also be in the same subnet as the LAN interface and the computers attached to it.
For example, if the LAN and USB interfaces are assigned addresses 10.0.0.2 and 10.0.0.3, respectively, then the PCs attached to either port can be assigned addresses in the range 10.0.0.4 through 10.0.0.254.
  1. If you are using IGMP on your network, click the IGMP Enable radio button.
  2. In the MTU field, enter the Maximum Transmission Unit size in bytes. This specifies the the largest Ethernet packet that the interface will accept. Packets larger than this size will be dropped.
  3. Click Save Changes.
  • If you changed the USB interface IP address while working from the USB-attached computer, then the connection will be terminated.
  • If you were using the Ethernet interface, a page will display to confirm your change and your connection will remain active.
  1. If necessary, reconfigure your USB PC so that its IP address places it in the same subnet as the new IP address of the USB interface.
  2. Open your web browser and log into the program by typing the new USB IP address in the address/location box.

NOTE: If want your changes to be permanent, be sure to Write Settings to Flash.