Appendix C - VPNs

Common VPN Situations

VPN Pass-throughFigure 78: 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 connec- tion.

∙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 GatewayFigure 79: 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 ADE-4300/ADW-4300 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 ADE- 4300/ADW-4300 supports IPsec ONLY.

∙Windows 2000 and Windows XP include an IPsec VPN client program. However, configuration of this client program for use with the ADE-4300/ADW-4300 is very complex and beyond the scope of this document.

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