Use of Global Discovery


(Jay Smith) #1

My apologies if this is a trivial question.

Under what circumstances would one want/need to use the Global Discovery option? I thought that it was to do with synchronizing with devices outside your LAN. However, I disabled this option in my Linux box, and my Android phone, using the data service of my provider (T-Mobile) seems to be able to synchronize with my Linux box without any problems. Thus, what is Global Discovery for exactly?


(Jakob Borg) #2

It is for connecting to devices outside of your LAN. I don’t know what happened in your test, specifically. Perhaps caching.


(Jay Smith) #3

I disabled Global Discovery in my Linux box. Restarted syncthing. In that Linux box, I copied a file to a directory shared with my Android phone - which, at the time, and for a few hours, was connected to the Internet via my T-Mobile data feed. One minute later or so, the file appeared in my phone. How does the caching that you mention work?


#4

Global discovery caches the data for some time. So if you disable it on your Linux box and the Android is already connected or tries to connect within a few minutes, while the IP of your Linux Box didn’t change, the Android still gets valid connection data.

Try to connect after a few hours and with a new IP from your home ISP, or disable global discovery on your phone, and you wil see, that they cannot connect.


(Jay Smith) #5

Tried that and, indeed, my Android device would not synchronize any longer. I enabled Global Discovery again in the Linux box, and the synchronization started working in the Android device immediately. Thanks so much for clarifying this.