We've made available for download VPN Configuration Guides for most of the gateways we support on our web site support section, and there are some on Linksys. VPN Configuration Guides are either written by our partners or by our engineering team. We do support Linksys RV082 and Linksys BEFVP41. You might want to look at our answer about Linksys WRV54G.

This depends on the type of cable/dsl router, however, to be sure that this function will work, TCP based NAT transparency must be enabled. Unfortunately, there is currently a bug in the MacOS-X client that prevents it from working properly so we currently have the Mac client using UDP based NAT transparency. When the bug is fixed, we will move back to TCP based NAT transparency. I am using Redhat 7.2 or above. I have installed the client, and when I try to use it it says I am connecting to 128. See similar questions...

Yes. A VPN can be used to add encryption to an APPX Router connection, as well as additional authentication. In addition, the APPX Router natively supports encrypted and authenticated sessions. See similar questions...

VPN stands for Virtual Private Network. It is a set of technologies that allow you to build secure "virtual" paths between hosts on insecure networks. The particular type of VPN Network Services is deploying is commonly known as a remote access or tunnel mode VPN. This acts very much like a classical dialup service, except you are using a data network rather than a voice network to make your "calls". See similar questions...

Make sure that you enable IPSec and PPTP in your hardware device or software configuration. Please, consult the manual of your firewall or router. See similar questions...