ZyXEL P-663H-51 Guia Do Utilizador

P-663H-51 User’s Guide

This chapter describes how to configure DNS settings.

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 DNS server 
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 ZyXEL Device supports the IPCP DNS server extensions through the 
DNS proxy feature.

The ZyXEL Device acts as a DNS proxy when the Primary and Secondary DNS Server 
fields are left blank in the LAN Setup screen.

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 LAN Setup screen. 

Click Advanced Setup > DNS > DNS Server to open the following screen.