H3C Technologies H3C S12500 Series Switches - Manual (Page 84)

71
The IP address configured with DNS spoofing is not the actual IP address of the requested domain
name, so the TTL of the DNS reply is set to 0 to prevent the DNS client from generating incorrect
domain name-to-IP address mappings.
3. Upon receiving the reply, the host sends an HTTP request to the replied IP address.
4. When forwarding the HTTP request through the dial-up interface, the device establishes a dial-up
connection with the network, and dynamically obtains the DNS server address through DHCP or
other autoconfiguration mechanisms.
5. When the DNS reply ages out, the host sends a DNS request to the device again.
6. Then the device operates the same as a DNS proxy. For more information, see "
728H
DNS proxy ."
7. After obtaining the IP address of the HTTP server, the host can access the HTTP server.
81B
DNS configuration task list
Tasks at a glance
(Required.)
729H
Configuring the IPv4 DNS client
(Optional.)
730H
Configuring the DNS proxy
(Optional.)
731H
Configuring DNS spoofing
(Optional.)
732H
Specifying the source interface for DNS packets
(Optional.)
733H
Configuring the DNS trusted interface
82B
Configuring the IPv4 DNS client
230B
Configuring static domain name resolution
Static domain name resolution allows applications such as Telnet to contact hosts by using host names
instead of IPv4 addresses.
On the public network or a VPN, each host name maps to only one IPv4 address. The most recent
configuration for a host name takes effect.
To configure static domain name resolution:
Step Command Remarks
1. Enter system view. system-view N/A
2. Configure a mapping between a
host name and an IPv4 address. ip host host-name ip-address
[ vpn-instance vpn-instance-name ]
By default, no mapping
between a host name and
an IPv4 address is
configured.
231B
Configuring dynamic domain name resolution
To use dynamic domain name resolution, configure DNS servers so that DNS queries can be sent to a
correct server for resolution. A DNS server manually configured takes precedence over the one
dynamically obtained through DHCP, and a DNS server configured earlier takes precedence. A name