A method for updating an Internet Protocol, IP, address, comprising: acquiring, by a proxy server, information of a pre-set server and Dynamic Domain Name Service, DDNS, server information of the pre-set server; wherein the pre-set server is a Local Area Network, LAN-side server, and the DDNS server is on an IPv6 network; identifying, by the proxy server, an IP address of the pre-set server according to the information of the pre-set server; and sending, by the proxy server, the IP address to a DDNS server indicated by the DDNS server information, wherein the information of the pre-set server comprises a Media Access Control, MAC, address of the pre-set server; and the DDNS server information comprises address information of the DDNS server, wherein the information of the pre-set server further comprises a domain name of the pre-set server registered on the DDNS server; and/or the DDNS server information further comprises information for identity authentication on the DDNS server, wherein the acquiring, by a proxy server, information of a pre-set server and DDNS server information of the pre-set server comprises: acquiring, by the proxy server, the information of the pre-set server and the DDNS server information of the pre-set server in an automatic configuration manner, wherein the acquiring, by the proxy server, the information of the pre-set server and the DDNS server information of the pre-set server in an automatic configuration manner comprises: receiving, by the proxy server, a Dynamic Host Configuration Protocol for Internet Protocol Version 6, DHCPv6, packet or a Route Solicitation, RS, packet from the pre-set server, wherein the DHCPv6 packet or the RS packet carries the information of the pre-set server and the DDNS server information of the pre-set server. acquiring, by a proxy server, information of a pre-set server and Dynamic Domain Name Service, DDNS, server information of the pre-set server; wherein the pre-set server is a Local Area Network, LAN-side server, and the DDNS server is on an IPv6 network; identifying, by the proxy server, an IP address of the pre-set server according to the information of the pre-set server; and sending, by the proxy server, the IP address to a DDNS server indicated by the DDNS server information, wherein the information of the pre-set server comprises a Media Access Control, MAC, address of the pre-set server; and the DDNS server information comprises address information of the DDNS server, wherein the information of the pre-set server further comprises a domain name of the pre-set server registered on the DDNS server; and/or the DDNS server information further comprises information for identity authentication on the DDNS server, wherein the acquiring, by a proxy server, information of a pre-set server and DDNS server information of the pre-set server comprises: acquiring, by the proxy server, the information of the pre-set server and the DDNS server information of the pre-set server in an automatic configuration manner, wherein the acquiring, by the proxy server, the information of the pre-set server and the DDNS server information of the pre-set server in an automatic configuration manner comprises: receiving, by the proxy server, a Dynamic Host Configuration Protocol for Internet Protocol Version 6, DHCPv6, packet or a Route Solicitation, RS, packet from the pre-set server, wherein the DHCPv6 packet or the RS packet carries the information of the pre-set server and the DDNS server information of the pre-set server. acquiring, by the proxy server, the information of the pre-set server and the DDNS server information of the pre-set server in an automatic configuration manner, wherein the acquiring, by the proxy server, the information of the pre-set server and the DDNS server information of the pre-set server in an automatic configuration manner comprises: receiving, by the proxy server, a Dynamic Host Configuration Protocol for Internet Protocol Version 6, DHCPv6, packet or a Route Solicitation, RS, packet from the pre-set server, wherein the DHCPv6 packet or the RS packet carries the information of the pre-set server and the DDNS server information of the pre-set server.