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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.
6.3 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.
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