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?


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.