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5.2 DNS Server Address 
DNS (Domain Name System) is for mapping a domain name to its corresponding 
IP address and vice versa, for example, the IP address of www.atlantis-land.com 
is 204.217.0.2. The DNS server is extremely important because without it, you 
must know the IP address of a machine before you can access it. The DNS 
server addresses that you enter in the DHCP setup 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 first 
is for an ISP to tell a customer the DNS server addresses, usually in the form of 
an information sheet, when s/he signs up. If your ISP gives you the DNS server 
addresses, enter them in the DNS Server fields in DHCP Setup, otherwise, leave 
them blank. 
Some ISP’s choose to pass the DNS servers using the DNS server extensions of 
PPP 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 ADSL Router supports the IPCP DNS server extensions 
through the DNS proxy feature. 
If the Primary and Secondary DNS Server fields in DHCP Setup are not specified, 
for instance, left as 0.0.0.0, the ADSL Router tells the DHCP clients that it itself is 
the DNS server. When a computer sends a DNS query to the ADSL Router, the 
ADSL Router forwards the query to the real DNS server learned through IPCP 
and relays the response back to the computer. 
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 menu. This way, the 
ADSL Router can pass the DNS servers to the computers and the computers can 
query the DNS server directly without the ADSL Router’s intervention. 
5.3 DNS Server Address Assignment 
Use DNS (Domain Name System) to map 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. 
There are two ways that an ISP disseminates the DNS server addresses. 
1. 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 DHCP Setup. 
2. Leave the DNS Server fields in DHCP Setup blank (for example 0.0.0.0). The 
ADSL Router acts as a DNS proxy when this field is blank. 
5.4 LAN TCP/IP 
The ADSL Router has built-in DHCP server capability that assigns IP addresses 
and DNS servers to systems that support DHCP client capability.