I have one always-on machine, a Raspberry Pi 3 B+, running Freedombox with Syncthing enabled. This server is accessible from the outside.
And then there are 4 mobile devices (2 laptops, 2 android smartphones) all syncing several folders with the little server, mostly pictures, where the pictures from phones are transferred to the laptops where they get processed and eventually archived.
The connection with one of the laptops keeps dropping. Only the server has Global Discovery enabled. When I restart the server, the transfer rate is high but drops after a few seconds to zero.
Sometimes in the log of that laptop it shows “External host has closed a connection”, but not always.
All machines, when at home, are behind the same firewall with the server.
Get the real (up-to-date) deal from apt.syncthing.net - v1.0.0 is approaching ancientness. And there was a biggish bug fixed in v1.0.1 - I don’t remember what it was but I do remember trying (unsuccessfully) to get it into debian before the freeze for the latest stable.
That’s conceptually wrong. When at home it doesn’t matter (local connections can be established), but otherwise it’s to be expected that the mobile devices aren’t directly reachable (corporate FW, mobile data, …) while the server is. So the mobile devices need global discovery to get the address of the server and reach it, while the other way around it probably won’t work.
And global discovery: What you “should” do is not change the defaults unless you have reason to, i.e. keep global discovery enabled on all clients. And I didn’t read any reason of yours yet (or missed it).