I am new to Syncthing and still very much playing with the various features while going through the documentation. One topic I could not find much information on is the Folder ID. Should Folder IDs be kept secret? Is a long, random Folder ID better than a short memorable one? Does the Folder ID have anything to do with how data is encrypted on transfer between devices? Any information for understanding Folder ID is welcome.
No, folder id is just an identifier that only matters between trusted devices.
So both Device ID as well as Folder ID are just identifiers.
However, device ID is generated by Syncthing, whereas Forlder ID can be set by user.
Is there a recommendation for the format of the Folder ID? I noticed two five digit blocks separated with a colon seem to be standard. Would “mysharedfolder” be an aceptable Folder ID? What happens if the Folder ID is not unique and some other device is syncing a different folder with the same Folder ID?
Folder id can be whatever you like. It’s random these days to prevent collisions, so all of your phones don’t just have a Camera folder id.
Device id is a bit more tricky, as it can be used to track your ip addresses over time, but there is no risk of making it public other than getting unwanted connections.
In that case, the data of both folders will be merged as soon as your device shares the folder with the other device.
That’s exactly why we added a folder label and generate the folder ID nowadays.
OK, so Folder ID is just an identifier, it can have any value/name, but needs to be unique among all connected devices. It’s best to just use the default value/name, as there is nothing to be gained from changing the ID.
Many thanks for the explanations!
It needs to be the same on two machines if the dataset in question is the same, as otherwise it’s just two separate datasets.
Needs to be the unique for each dataset shared between connected devices.
Edit: Folder ID is just an identifier, it can have any value/name, but needs to be unique for each dataset (shared folder) among all connected devices. It’s best to just use the default value/name, as there is nothing to be gained from changing the ID.