When Apple switched to the hybrid XNU kernel with Mac OS X 10.0 in 2001, they decided not to port the typical AppleTalk network protocol group to the new operating system. The fact that the electronics giant didn’t intend to develop an adequate successor didn’t suit the Mac user Stuart Cheshire in the least, so he set up an e-mail discussion board in which he addressed the weaknesses of the necessary manual network configuration together with other users. This got Apple to rethink their decision: Without delay, Stuart Cheshire was introduced and commissioned to develop a protocol variant for the new operating system, which resulted in the aforementioned cooperation with the Internet Engineering Task Force.
With Mac OS X 10.2, Apple published the first version of the new protocol specification in August 2002 under the name Rendezvous. Due to legal problems, they were forced to find a new title for the project, which is why the network software has had the name Bonjour since Version 10.4. The main component of the packet is the mDNSResponder, a program that begins on start-up and runs in the background, and implements Multicast DNS and DNS-Based Service Discovery. The internet protocol specification IPv4LL (or IPv6LL) is of course also one of the main components. With it, the Apple solution covers the three elementary areas of the configuration-free network:
- Addressing
- Name resolution
- Network service identification
Thanks to this architecture, you can easily connect to other components in local networks that are also based on Bonjour – regardless of whether it’s a PC, printer, or some other application. For example, the Apple music service iTunes uses the technology to automatically find other users who are sharing their music on the network. On common macOS and iOS systems, the Bonjour software is automatically installed. Windows users can either download a specific version for printing services or install an application whose environment contains the software. These include, among others, the previously mentioned iTunes, Skype, and Adobe Photoshop (CS3 and higher).
An alternative to Apple’s zeroconf solution that functions on Linux systems as well, installed by default on Debian and Ubuntu and available under the free license LGPL, is Avahi. The implementation initially received support from the non-profit initiative freedesktop.org, but has now developed into an independent project.