Appendix B - About VPNs
Common VPN Situations
VPN Pass-through
Figure 60: VPN Pass-through
Here, a PC on the LAN behind the Router/Gateway is using VPN software, but the
Router/Gateway is NOT acting as a VPN endpoint. It is only allowing the VPN connection.
•
The PC software can use any VPN protocol supported by the remote VPN.
•
The remote VPN Server must support client PCs which are behind a NAT router, and so
have an IP address which is not valid on the Internet.
•
The Router/Gateway requires no VPN configuration, since it is not acting as a VPN
endpoint.
Client PC to VPN Gateway
Figure 61: Client PC to VPN Server
In this situation, the PC must run appropriate VPN client software in order to connect, via the
Internet, to the ADSL2/2+ Broadband Router or other VPN Gateway. Once connected, the
client PC has the same access to LAN resources as PCs on the local LAN (unless restricted by
the network administrator).
•
IPsec is not the only protocol which can be used in this situation, but the ADSL2/2+
Broadband Router supports IPsec ONLY.
•
Windows 2000 and Windows XP include an IPsec VPN client program. However,
configuration of this client program for use with the ADSL2/2+ Broadband Router is very
complex and beyond the scope of this document.
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