Dns Proxy - 3Com 4500G Family Configuration Manual

If an alias is configured for a domain name on the DNS server, the device can resolve the alias into the
IP address of the host.

DNS Proxy

Introduction to DNS proxy
A DNS proxy forwards DNS requests and replies between DNS clients and a DNS server.
As shown in Figure
request to the designated DNS server, and conveys the reply from the DNS server to the client.
The DNS proxy simplifies network management. When the DNS server address is changed, you only
need to change the configuration on the DNS proxy instead of on each DNS client.
Figure 1-2 DNS proxy networking application
Operation of a DNS proxy
1) A DNS client considers the DNS proxy as the DNS server, and sends a DNS request to the DNS
proxy, that is, the destination address of the request is the IP address of the DNS proxy.
2) The DNS proxy searches the local static domain name resolution table and dynamic domain name
resolution table after receiving the request. If the requested information is found, the DNS proxy
returns a DNS reply to the client.
3) If the requested information is not found, the DNS proxy sends the request to the designated DNS
server for domain name resolution.
4) After receiving a reply from the DNS server, the DNS proxy forwards the reply to the DNS client.
1-2, a DNS client sends a DNS request to the DNS proxy, which forwards the
1-3