User guide

ADSL2+ Ethernet USB Combo Router - User Guide
Page 16 of 67
4.3 LAN / DHCP Configuration
On one side of your ADSL Router, you have your own Local Area Network (LAN) connections.
This is where you plug in your local computers to the ADSL Router. The ADSL Router is
normally configured to automatically provide all the PC's on your network with Internet
addresses.
To enable or disable DHCP, click Basic, then select LAN Configuration. The Start IP Address is
where the DHCP server starts issuing IP addresses. This value must be greater than the ADSL
Router IP address value. For example if the ADSL Router IP address is 192.168.1.1 than the
starting IP address must be 192.168.1. 2 (or higher).
The End IP Address is where the DHCP server stops issuing IP addresses. The ending address
cannot exceed a subnet limit of 254. Hence the max value for our default gateway is
192.168.1.254. If the DHCP server runs out of DHCP addresses, users will not get access to
network resources. If this happens you can increase the Ending IP address (to the limit of 255) or
reduce the lease time.
The Lease Time is the amount of time a network user will be allowed connection to the ADSL
Router with their current dynamic IP address. The amount of time is in units of minutes; the
default value is 3600 minutes (60 hours).
Note: If you change the start or end values, make sure the values are still within the same subnet
as the gateways IP address. In other words, if the gateways IP address is 192.168.1.1 and you
change the DHCP start/end IP addresses to be 192.128.1.2/192.128.1.100, you will not be able to
communicate to the ADSL Router if your PC has DHCP enabled.
In addition to the DHCP server feature, the ADSL Router supports the DHCP relay function.
When the ADSL Router is configured as DHCP server, it assigns the IP addresses to the LAN
clients. When the ADSL Router is configured as DHCP relay, it is responsible for forwarding the
requests and responses negotiating between the DHCP clients and the server.
By turning off the DHCP server and relay the network administrator must carefully configure the
IP address, Subnet Mask and DNS settings of every computer on your network. Do not assign
the same IP address to more than one computer and your ADSL Router must be on the same
subnet as all the other computers. See Figure 1-7.