DSL-300T ADSL Modem User’s Guide
address (each computer must have a unique address to distinguish it on the network). The IP address scheme used in Example #1 can be used for any LAN that requires up to 253 separate IP addresses (excluding the Modem). Notice that the subnet mask is the same for all machines and the default gateway address is the LAN IP address of the Modem.
It is a good idea to make a note of each device’s IP address for reference during troubleshooting or when adding new stations or devices.
Using DHCP
The second way to use the default settings is to allow the Modem to automatically assign IP settings for workstation using DHCP. To do this, simply make sure your computers’ IP addresses are set to 0.0.0.0 (under Windows, choose the option Obtain an IP address automatically in the TCP/IP network component described above). When the computers are restarted, their IP settings will automatically be assigned by the Modem. The Modem is set by default to use DHCP. See the discussion in Chapter 5 for information on how to use configure the Modem for DHCP.
Changing the IP Address of the Modem
When planning your LAN IP address setup, you may use any scheme allowed by rules that govern IP assignment. It may be more convenient or easier to remember an IP scheme that use a different address for the Modem. Or you may be installing the Modem on a network that has already established the IP settings. Changing the IP address is a simple matter and can be done using the web manager. If you are incorporating the Modem into a LAN with an existing IP structure, be sure to disable the DHCP function. Also, consider the effects of the NAT function - which is enable by default.
An IP addressing scheme commonly used for Ethernet LANs establishes 10.0.0.1 as the base address for the network. Using Example #2 below, the Modem is assigned the base address 10.0.0.1 and the remaining addresses are assigned manually or using DHCP.
Alternative IP Assignment
Host | IP Address | Subnet Mask | Gateway IP |
Modem | 10.0.0.1 | 255.255.255.0 |
|
Computer #1 | 10.0.0.2 | 255.255.255.0 | 10.0.0.1 |
Computer #2 | 10.0.0.3 | 255.255.255.0 | 10.0.0.1 |
Computer #3 | 10.0.0.4 | 255.255.255.0 | 10.0.0.1 |
| IP Setup - Example #2 |
| |
These two examples are only examples you can use to help you get started. If you are interested in more advanced information on how to use IP addressing on a LAN there are numerous resources freely available on the Internet. There are also many books and chapters of books on the subject of IP address assignment, IP networking and the TCP/IP protocol suite.
46