Method for obtaining DNS and tunnel gateway device

1. A tunnel gateway device based on a tunnel, in which both ends of the tunnel include the tunnel gateway device and a tunnel network side device, an automatic control server manages the tunnel gateway device through an internet, the tunnel gateway device is connected to an IPv6 or IPv4 network through the tunnel network side device, and a domain name DNS server which is used for a service in an inner layer of the tunnel lies in the IPv6 or IPv4 network, wherein the tunnel gateway device is configured to:

receive a domain name system DNS server address for an inner layer or an outer layer service of a tunnel configured by an automatic control server according to a TR069 protocol; and

when the configured DNS server address is for either the inner layer or the outer layer service of the tunnel and before the client initiates a DNS request, take a tunnel gateway device address as the DNS server address and send the tunnel gateway device address to a client; then, after receiving the DNS request sent by the client, search DNS items stored locally, if there is a matched DNS item in the tunnel gateway device, obtain a corresponding IP address information according to the matched DNS item; if there is no matched DNS item in the tunnel gateway device, send the DNS request to a DNS server according to the configured DNS server address and receive a DNS response returned by the DNS server, so as to obtain the matched DNS item from the DNS server and accordingly obtain the corresponding IP address information according to the matched DNS item;

when the configured DNS server address is only for the inner layer service of the tunnel and before the client initiates a DNS request, send the configured DNS server address to the client; then, after receiving the DNS request sent by the client, not identify the DNS request, but directly encapsulate the DNS request into the outer layer of tunnel, then transparently transmit the DNS request to a DNS server; and transparently transmit a DNS response returned by the DNS server to the client, so that the tunnel gateway device does not participate in the interactive control of the DNS information but only performs the transparent transmission;

wherein the tunnel gateway device supports at least one of a slight-level dual stack-lite (DS-LITE) and an IPv6 rapid deployment (6rd) technology, wherein an IPv6 DNS server of the 6rd is configured according to the TR069 protocol and an IPv4 DNS server of the DS-LITE is configured according to the TR069 protocol.

2. The device according to claim 1 , wherein,

the tunnel gateway device is further configured to: store the DNS item obtained from the DNS server, and when storing the DNS item, if local DNS item record is already full, then delete the local DNS item according to an aging policy.

3. A method for obtaining a domain name system DNS based on a tunnel, in which both ends of the tunnel include a tunnel gateway device and a tunnel network side device, an automatic control server manages the tunnel gateway device through an internet, the tunnel gateway device is connected to an IPv6 or IPv4 network through the tunnel network side device, and a domain name DNS server which is used for a service in an inner layer of the tunnel lies in the IPv6 or IPv4 network, wherein the method comprises:

an automatic control server configuring a domain name system DNS server address for an inner layer or an outer layer service of a tunnel on a tunnel gateway device according to a TR069 protocol; and

when the configured DNS server address is for either the inner layer or the outer layer service of the tunnel and before the client initiates a DNS request, the tunnel gateway device taking a tunnel gateway device address as the DNS server address and sending the tunnel gateway device address to a client; then, after receiving the DNS request sent by the client, searching DNS items stored locally, if there is a matched DNS item in the tunnel gateway device, obtaining a corresponding IP address information according to the matched DNS item; if there is no matched DNS item in the tunnel gateway device, sending the DNS request to a DNS server according to the configured DNS server address and receiving a DNS response returned by the DNS server, so as to obtain the matched DNS item from the DNS server and accordingly obtain the corresponding IP address information according to the matched DNS item;

when the configured DNS server address is only for the inner layer service of the tunnel and before the client initiates a DNS request, the tunnel gateway device sending the configured DNS server address to the client; then, after receiving the DNS request sent by the client, not identifying the DNS request, but directly encapsulating the DNS request into the outer layer of tunnel, then transparently transmitting the DNS request to a DNS server; and transparently transmitting a DNS response returned by the DNS server to the client, so that the tunnel gateway device does not participate in the interactive control of the DNS information but only performs the transparent transmission;

wherein the tunnel gateway device supports at least one of a slight-level dual stack-lite (DS-LITE) and/or an IPv6 rapid deployment (6rd) technology, wherein an IPv6 DNS server of the 6rd is configured according to the TR069 protocol and wherein an IPv4 DNS server of the DS-LITE is configured according to the TR069 protocol.

4. The method according to claim 3 , further comprising,

the tunnel gateway device storing the DNS item obtained from the DNS server, and when storing the DNS item, if local DNS item record is already full, then deleting the local DNS item according to an aging policy.