I have used TeamViewer Portable several times, it runs well although with frequent disconnection, however I think that it is caused by the bad internet connection.
Now, I want to use the VPN facility, unfortunately that the software require installation of its driver.
Is there any solution to avoid installing the driver?
Update on 20 September 2011:
My conclusion is: There is no such thing like portable TeamViewer for VPN service.
The discussions below have been about installing TAP driver into the client computer, which is absolutely out of my consideration as a purist in portable software user