It's been asked many times for a LAN syncing mode, and every time people are referred to the hack that is clicking on each folder and manually deselecting relay, tracker, and DHT. This is horrible design from a security point of view. Lack of security is the default - if someone misses a single checkbox or forgets to set a single folder, they are now insecure. Furthermore, when a new folder is added to sync, because it defaults to broadcast to the world, before a user even has a chance to change the settings, a broadcast will go out announcing the files. I realize that the developers claim that this all BitTorrent Sync communications on the Internet are private, and promise that we can trust them not to read our files. However, this is really not good enough for a lot of sensitive information (and presumably they understand that, which is why it's possible to disable relay, tracker, and DHT in the first place). The app is closed source, so we just need to take promises on faith, and even assuming everyone is honest, the data is only one security bug in the code away from the prying eyes of bad guys. For a lot of sensitive data, given that we can't read the BitTorrent Sync source code, the only security that is good enough is being able to ensure by monitoring the network that Sync never, ever communicates outside of the LAN. This is all in addition to the fact that it's incredibly obtuse and burdensome for a user to go through each folder individually clicking options, to the point where this needs to be a question on the FAQ. Now I can appreciate for the average user, you want things to be as simple as possible and just work. However, for an app that claims to be serious about security and privacy, based on best practices in security design, there really needs to be a global option to limit all communications to LAN rather than this current folder-by-folder approach.