Syncthing Docker container won't connect to relays

[AudriusButkevicius]

Perhaps thats only usable at build time, not obvious.

[bt90]

https://pkg.go.dev/net#hdr-Name_Resolution

Try this:

GODEBUG=netdns=go+1

You can also check if your docker-compose config is proper yml:

docker-compose config

[nineheadnaga]

Yes, I had read that go.dev page from the Golang article linked by Audrius… but I think it’s like he says, it works only at build, since it keeps using the same resolver no matter what I set. It even says so in the logs, "go package net: built with netgo build tag":

syncthing | [26ZZZ] 2021/12/21 23:15:55.575134 relay_listen.go:57: INFO: Relay listener (dynamic+https://relays.syncthing.net/endpoint) starting
syncthing | [26ZZZ] 2021/12/21 23:15:55.575758 dynamic.go:49: DEBUG: DynamicClient:0x4000099c80:<nil>@dynamic+https://relays.syncthing.net/endpoint looking up dynamic relays
syncthing | [26ZZZ] 2021/12/21 23:15:55.581455 dynamic.go:59: DEBUG: DynamicClient:0x4000099c80:<nil>@dynamic+https://relays.syncthing.net/endpoint failed to lookup dynamic relays Get "https://relays.syncthing.net/endpoint": dial tcp: lookup relays.syncthing.net on [::1]:53: dial udp [::1]:53: connect: cannot assign requested address
syncthing | [26ZZZ] 2021/12/21 23:15:55.581747 relay_listen.go:65: INFO: Relay listener (dynamic+https://relays.syncthing.net/endpoint) shutting down

(oh, and apparently the config file is proper yml).

[nineheadnaga]

Ok gentlemen, sorry for not following up these past few days, I was trying some things (plus there was xmas with family). The good news is that everything is working now! After trying everything and not getting anywhere I decided to take a radical approach, use a previous image I saved of my SBC’s microSD, and reinstall Docker and Syncthing container from scratch. And it works! I could connect to the relays and do remote syncing without UPNP or anything like that. The bad news is that by doing that, I have no idea what was the real issue blocking the sync from working. Maybe something in Docker wasn’t working right, like Audrius said… who knows.

Many, many thanks anyway everybody for your help, patience and time in trying to troubleshoot this issue with me. Happy holidays!