why do I have 2 listeners?

I followed someone’s instructions on how to setup syncthing so that it directly syncs data between a PC and a smartphone without connecting to any servers (NAT traversal, local discovery, global discovery and relaying are all turned off). At the end of the tutorial on his interface it says 1/1 listeners and for me it says 2/2 even though I did everything exactly like him. Why is that?

Did you check how old the guide is? Syncthing nowadays uses regular TCP connections and UDP based QUIC connections. The later ones have the benefit of NAT traversal. That’s why syncthing is listening on 22000/tcp and 22000/udp.

The guide is from February 9th 2021. So having 2 listeners is normal then? I was worried for a second there.

Isn’t it best to ask whoever wrote the tutorial?

At this point there is not enough information to provide a sensible answer.

He has a popular blog that he does on the side - in addition to his normal job - and doesn’t answer to questions to his blog because he gets bombarded with so many e-mails that he can’t answer them all. That’s why I thought maybe you guys could help me.

Well, we don’t even know what the blog suggests, so I am not sure how we could provide any advice.

You can hover on the listeners and it will tell you which ones are running.

Hovering on listeners doesn’t work, unfortunately. Hovering on the right to local state, download/upload rate and version works though. I’m on a 64-bit Windows install.

:man_shrugging: sorry, my psychic powers are not strong enough.

What are we investigating? This it exactly what it should look like.

This it exactly what it should look like.

That’s all I wanted to hear, really. I was unsure, if anything was wrong with my setup because the instructions I followed had it differently and “listeners” sounded to me like there was a second device that “listens” to the data that my PC pushes. That had me a bit unsettled, that’s all.

The term listener (in a network context) is fairly well known along developers, but less known among users.

Syncthing is always “listening” for connections (that is, it awaits new incoming connection requests). This is neccessary, as otherwise no devices could connect. The amount of listeners depends on the number of connection mechanisms (e.g sockets) syncthing uses. Syncthing has a number of transport mechanisms, including TCP, UDP (QUIC) and relays. All of these are end-to-end encrypted (via TLS). As you have disabled relays, you only have TCP and QUIC, which is why it shows 2 listeners (in other words: “syncthing is awaiting connections via 2 mechanisms”.

Thank you very much, that cleared things up for me.

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