Codebook utilizes software developed by Apple called Bonjour, an implementation of zero-configuration networking (zeroconf) for service discovery and hostname resolution to allow for local WiFi synchronization. Codebook running on the desktop will advertise a service over the local network on port 57419 that Codebook on mobile devices will scan for to initiate a WiFi synchronization.
Often times, Bonjour may already be installed on desktop machines that have iTunes already installed. When Codebook for Windows is installed, if the user opts to include Desktop WiFi synchronization support and Bonjour is not found on the machine, a supplemental package is downloaded and verified from the Apple website to install for the user.