Chapter 8 Home Networking
EMG6726/8726-B10A User’s Guide
124
Figure 72
LAN and WAN IP Addresses
8.9.2 DHCP Setup
DHCP (Dynamic Host Configuration Protocol, RFC 2131 and RFC 2132) allows individual clients to obtain
TCP/IP configuration at start-up from a server. You can configure the EMG as a DHCP server or disable it.
When configured as a server, the EMG provides the TCP/IP configuration for the clients. If you turn DHCP
service off, you must have another DHCP server on your LAN, or else the computer must be manually
configured.
IP Pool Setup
The EMG is pre-configured with a pool of IP addresses for the DHCP clients (DHCP Pool). See the product
specifications in the appendices. Do not assign static IP addresses from the DHCP pool to your LAN
computers.
8.9.3 DNS Server Addresses
DNS (Domain Name System) maps a domain name to its corresponding IP address and vice versa. The
DNS server is extremely important because without it, you must know the IP address of a computer
before you can access it. The DNS server addresses you enter when you set up DHCP are passed to the
client machines along with the assigned IP address and subnet mask.
There are two ways that an ISP disseminates the DNS server addresses.
• The ISP tells you the DNS server addresses, usually in the form of an information sheet, when you sign
up. If your ISP gives you DNS server addresses, enter them in the
DNS Server
fields in the
DHCP Setup
screen.
• Some ISPs choose to disseminate the DNS server addresses using the DNS server extensions of IPCP (IP
Control Protocol) after the connection is up. If your ISP did not give you explicit DNS servers, chances
are the DNS servers are conveyed through IPCP negotiation. The EMG supports the IPCP DNS server
extensions through the DNS proxy feature.
Please note that DNS proxy works only when the ISP uses the IPCP DNS server extensions. It does not
mean you can leave the DNS servers out of the DHCP setup under all circumstances. If your ISP gives
you explicit DNS servers, make sure that you enter their IP addresses in the
DHCP Setup
screen.