The client has the option of downloading TeamViewer QuickSupport. It is a simple, non-installed program which runs with a single double-click that will provide a PARTNER ID that the client gives to you. That PARTNER ID allows TeamViewer to navigate the multiple NATs likely between you and the client, and establish a connection.
Neither side has to install a program. For the Client, there is TeamViewer QuickSupport. For the Controller, there is TeamViewer Portable.
EDIT: Let me clarify however that the Linux version of TeamViewer always requires installation on that machine. Windows and Mac versions have the options of just having a non-installed QuickSupport mode.
Are you saying that it is a TSR (resident) program ?
And if that is the case, isn't this still in reality a program that is "installed" on the client/system to be monitored, just a resident or background program ?
Also, are you saying that this QS module has to be downloaded/installed everytime it is wanted to be used or is it called/loaded as a resident / startup program each time the computer is booted ?
Nevermind, I called Teamviewer and if I am understanding them correctly, the executable has to be run each and every time I would want to have access & control of the remote computer and is ended if either the remote session or if the computer is rebooted, i.e. not loaded on startup.
Thanks.