17

DNS Route

17.1 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 P-2812HNU-51c uses a system DNS server (in the order you specify in the WAN > Internet Connection screen) to resolve domain names that do not match any DNS routing entry. After the P-2812HNU- 51c 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 ptm0.100 is set to be the system DNS server. The DNS server

10.10.23.7is obtained from the WAN interface ppp1.123. You configure a DNS route for *example.com to have the P-2812HNU-51c 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 154 Example of DNS Routing Topology

LANWAN

ptm0.100 DNS:168.92.5.1 (Default)

ppp1.123

sip.service.com

 

mail.example.com

DNS:10.10.23.7

 

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P-2812HNU-51c User’s Guide