DNS proxy configuration example

When the IP address of the DNS server changes, you must configure the new IP address of the DNS server on each device on the LAN. To simplify network management, you can use the DNS proxy function.

As shown in Figure 34, specify Device A as the DNS server of Device B (the DNS client). Device A acts as a DNS proxy. The IP address of the real DNS server is 4.1.1.1.

Configure the IP address of the DNS proxy on Device B. DNS requests of Device B are forwarded to the real DNS server through the DNS proxy.

	NOTE: Before performing the following configuration, assume that Device A, the DNS server, and the host are reachable to each other and the IP addresses of the interfaces are configured as shown in Figure 34.

1. Configure the DNS server

This configuration may vary with different DNS servers. When a Windows server 2000 PC acts as the DNS server, see "Dynamic domain name resolution configuration example" for related configuration information.

1. Configure the DNS proxy

# Specify the DNS server 4.1.1.1.

<DeviceA> system-view
[DeviceA] dns server 4.1.1.1

# Enable DNS proxy.

[DeviceA] dns proxy enable

1. Configure the DNS client

# Enable the domain name resolution function.

<DeviceB> system-view
[DeviceB] dns resolve

# Specify the DNS server 2.1.1.2.

[DeviceB] dns server 2.1.1.2

1. Configuration verification

# Execute the ping host.com command on Device B to verify that the communication between the device and the host is normal and that the corresponding destination IP address is 3.1.1.1.

[DeviceB] ping host.com
Trying DNS resolve, press CTRL_C to break
 Trying DNS server (2.1.1.2)
  PING host.com (3.1.1.1):
  56  data bytes, press CTRL_C to break
    Reply from 3.1.1.1: bytes=56 Sequence=1 ttl=126 time=3 ms
    Reply from 3.1.1.1: bytes=56 Sequence=2 ttl=126 time=1 ms
    Reply from 3.1.1.1: bytes=56 Sequence=3 ttl=126 time=1 ms
    Reply from 3.1.1.1: bytes=56 Sequence=4 ttl=126 time=1 ms
    Reply from 3.1.1.1: bytes=56 Sequence=5 ttl=126 time=1 ms

  --- host.com ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 1/1/3 ms