BackupPC

In 2007, BackupPC was mentioned as one of the three most well known open-source backup software,[2] even though it is one of the tools that are "so amazing, but unfortunately, if no one ever talks about them, many folks never hear of them".

[4] BackupPC incorporates a Server Message Block (SMB) client that can be used to back up network shares of computers running Windows.

Paradoxically, under such a setup the BackupPC server can be located behind a NAT'd firewall while the Windows machine operates over a public IP address.

[5] It can back up Unix-like systems with native ssh and tar or rsync support, such as Linux, BSD, and OS X, as well as Microsoft Windows shares with minimal configuration.

[6] On Windows, third party implementations of tar, rsync, and SSH (such as Cygwin) are required to utilize those protocols.

[8] BackupPC uses a combination of hard links and compression to reduce the total disk space used for files.