Configuring VPN
VPN
Configuration Guide
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1
VPN
1.1 Overview
VPN (Virtual Private Network) provides a means for secure communication between
remote computers across a public wide area network (WAN), such as the internet. Virtual
indicates the VPN connection is based on the logical end-to-end connection instead of the
physical end-to-end connection. Private indicates users can establish the VPN connection
according to their requirements and only specific users are allowed to use the VPN
connection.
The core of VPN is to realize tunnel communication, which fulfills the task of data
encapsulation, data transmission and data decompression via the tunneling protocol.
Common tunneling protocols are Layer 2 tunneling protocol and Layer 3 tunneling
protocol.
Figure 1-1 Typical Topology of VPN
Remote Client
Gateway (Client)
Enterprise Server
Gateway (Server)
Internet
VPN Tunnel
1.2 Supported Features
The router supports Layer 2 tunneling protocol (PPTP, L2TP) and Layer 3 tunneling
protocol (IPSec).
PPTP
PPTP (Point-to-Point Tunneling Protocol) is a network protocol that enables the secure
transfer of data from a remote client to a private enterprise server by creating a VPN
across TCP/IP-based data networks. PPTP supports on-demand, multiprotocol, virtual
private networking over public networks, such as the internet.
L2TP
L2TP (Layer 2 Tunneling Protocol) provides a way for a dialup user to make a virtual Point-
to-Point Protocol (PPP) connection to an L2TP network server (LNS), which can be a
security gateway. L2TP sends PPP frames through a tunnel between an L2TP access
concentrator (LAC) and the LNS. Because of the lack of confidentiality inherent in the L2TP
protocol, it is often implemented along with IPSec.