L2TP over IPSEC remote access method and device

The invention discloses a method and a device for remote access of L2TP over IPSEC, separating a bi-layer tunnel agreement network server module from an IP security protocol module; the method comprises: the IP security protocol module provides a security strategy mode for remote access and configures the module for the remote access of the L2TP over IPSEC; when the remote access of the L2TP overIPSEC is confirmed, a data base of IP security protocol strategy is established and maintained; the public net address and public net end number are taken as the indexing key words of the data base with security strategy, and the message getting through the remote access of the L2TP over IPSEC is subject to encapsulation and decapsulation and is retransmitted by routing. The invention can supporta plurality of remote access users in a same privately owned network to use a same public net address after NAPT and support the separation of LNS from IPSEC.