I'd like to setup a remote backup using the Windows client (i.e. a machine located in a remote site to be backed up to my Amanda server).

Do / should I setup a VPN or can I use the client "as is" (by opening the necessary ports in the firewall for the client to "talk" with the server) ? Does it do encryption by itself ?

I have tried to go through the documentation but could not really find a a definitive answer for this question...