Like most people, I'm not doing offsite backup of my data. Are there any low power/cost end to end solutions that I could plug into my friend's home network and backup data from my home?
Crashplan does exactly as you mention, and handles jumping through NAT, encryption (with your own keys if you want), etc:<p><a href="http://crashplan.com/" rel="nofollow">http://crashplan.com/</a><p>Cross platform (Mac/Win/Linux/Solaris). Some extra features unlock if you buy the + version.<p>If you want a totally free solution that would take a little more work to implement, look at Duplicity:<p><a href="http://duplicity.nongnu.org/" rel="nofollow">http://duplicity.nongnu.org/</a><p>rsync based, uses SSH/GnuPG for security.<p>Run one of these on whatever hardware you have available.
You can easily tunnel rsync over SSH. You can configure even the simplest routers to do port-forwarding, e.g. your friend's external IP on port 2222 is redirected to port 22 on an internal host.<p>Rsnapshot (rsnapshot.org) is a free rsync-based backup system; it is very efficient in terms of disk space and keeps full backups, but only keeps 1 copy of each file.
you might be able to use local-drive backup software, a drive at your friend's home, and a pogoplug device to access the drive remotely as if it were a local drive.<p><a href="http://pogoplug.com/" rel="nofollow">http://pogoplug.com/</a><p>and you could use TrueCrypt to add an additional level of security.