Problem with relays

Hi all,

I’m using syncthing in two computers, one at home behind a NAT router and one at my office behind several pretty restrictive firewalls (although that wasn’t a problem until short ago).

A few days back I startes having trouble, both machines show the other as disconnected. I’m pretty sure, because of the firewall restrictions and the lack of UPNP at my office that the need a relay server.

The PC at my office reports three addresses for the one at home (one TCP and two relays). However, my PC at home only reports one address for the one at my office and is TCP and no relays (and I’m pretty sure the TCP address in that case is useless).

Both computers report on the console to be connected to relays. I think that’s the reason why they can’t connect to each other (although not a 100% sure).

I’m using ubuntu 16.04 on both and Syncthing 0.14.3.

Any ideas? Maybe a way to force the one at my office to only broadcast a relay address?


It advertises relays via discovery if it can connect to one. It seems that they cannot connect to one in your case.

Thanks for the prompt response.

Still seems strange, as both computers claim to be connected to relays on the respective consoles. Also, some days ago it was working perfectly…

Are you using syncthing-gtk?

Do they both have a dynamic as the address of the other?

These may be related:

No, I’m not using syncthing-gtk. Just plain syncthing for linux.

The computer at my office claims to be connected to relay:// (443 is one of the allowed outbound ports at my work). However it doesn’t see my computer at home. I will try to change the port at home to some of the allowed outbound ports at my office to see if that works.

The same problem for me with 0.14.3 (ir works good on the 0.12 branch).

My servers can’t join nor via my relay server, nor via public relays.

Syncthing 0.14.4 - relays still doesn’t work.

Looks like something wrong with addresses with relays. syncthing displays remote computer address as relay.

cache.go:139: DEBUG: addresses: [relay://:<relay_port>,…

I’m expecting relay address instead remote address in the relay:// notation says otherwise.

You have to be more specific and provide full detailed logs, as “it doesn’t work” won’t help solve the problem.

Are you running your own discovery server?

No, I’m running my own relay server, not discovery.

Notation of relay and “Sync Protocol Listen Addresses” was changed since 0.12. Probably, that’s source of issue.

When I changed “Sync Protocol Listen Addresses” into “default”, then syncthing 0.14 was connected via some public relay and it works good. So, probably just correct notation should be used for “Sync Protocol Listen Addresses”?

The correct notation is documented at

Static relay address (relay://…) Syncthing will connect to and listen for incoming connections via the specified relay address.

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