Netatalk is an OpenSource software package, that can be used to turn a *NIX machine into an extremely high-performance and reliable file server for Macintosh computers.
Using Netatalk's AFP 3.3 compliant file-server leads to significantly higher transmission speeds compared with Macs accessing a server via SaMBa/NFS while providing clients with the best possible user experience (full support for Macintosh metadata, flawlessly supporting mixed environments of classic Mac OS and OS X clients)