Mac OS normally doesn’t allow you to use network shares as targets for TimeMachine backups. This can be worked around, tho. 🙂
First you need to tweak Mac OS to accept network shares by entering the following command in a Terminal session:
defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1
That would already allow you to store your backups on a network share. But do you really want to trust your valuable data to a network share that can potentially be accessed by untrusted users, such as your favorite bastard admin from hell?! :)
Here’s when the following comes in:
You will create an encrypted sparse bundle and use it as a target for the backup.