Backup of a Debian machine to an Apple Time Capsule I have two Macs, backed up on a 3TB Apple Time Capsule. But I also have a Debian machine on the same local network, and I would like to back it up (at least one of its hard disks) on the same Apple Time Capsule. Is this possible?

To prevent misunderstandings: I found zillions of places on the Web where people explain how to use a Debian machine as a cheaper version of Apple Time Capsule. This is not what I need. What I need is to back up the Debian machine on a (real) Apple Time Capsule. Thanks in advance for any advice!
In AirPort Utility, turn off the backup feature, turn off disk encryption, and turn on disk sharing with a password. Now you can connect to the disk over the network using the AFP protocol.

In most graphical file explorers you can now connect to the disk using the address afp://&lt;ip-address-of-airport&gt;. To easily configure scheduled backups to the device, you can check out Déjà Dup (known as simply “Backup” in Ubuntu).

You cannot backuo your Macs using Time Machine and your Linux machine to the same device. The two setups are incompatible as Time Machine requires proprietary extension to AFP. I would recommend you get a cheap Raspberry Pi and a two-terabyte power-over-USB-external-disk to host your Linux backup needs. (Install openssh and ufw, and you’re basically done setting up a simplistic firewalled backup device on the cheap.)