ZyXEL Communications P660HN-Fx User Manual

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ADSL Series User’s Guide
161
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H A P T E R
      9
DNS Route
9.1  Overview   
DNS (Domain Name System) is for mapping 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 machine before you can access it. 
In addition to the system DNS server(s), each WAN interface (service) is set to have its own static 
or dynamic DNS server list. You can configure a DNS static route to forward DNS queries for certain 
domain names through a specific WAN interface to its DNS server(s). The ZyXEL Device uses a 
system DNS server (in the order you specify in the Broadband screen) to resolve domain names 
that do not match any DNS routing entry. After the ZyXEL Device receives a DNS reply from a DNS 
server, it creates a new entry for the resolved IP address in the routing table.
In the following example, the DNS server 168.92.5.1 obtained from the WAN interface atm0.100 is 
set to be the system DNS server. The DNS server 10.10.23.7 is obtained from the WAN interface 
ppp1.123. You configure a DNS route for *example.com to have the ZyXEL Device forward DNS 
requests for the domain name mail.example.com through the WAN interface ppp1.123 to the DNS 
server 10.10.23.7.
Figure 75   
Example of DNS Routing Topology
9.1.1  What You Can Do in this Chapter
The DNS Route screens let you view and configure DNS routes on the ZyXEL Device (
WAN
LAN
atm0.100
ppp1.123
DNS:10.10.23.7
DNS:168.92.5.1
sip.service.com
mail.example.com
(Default)