"Allow incoming connections" disabled but still upload activity present

[takuma sato]

I was testing with this option to see what happened if I unchecked this box, I expected that by disabling it no one would be able to reach the node and thus request to download from me wouldn't happen resulting in a flat 0 kb/s line for upload rate, however after a while I saw uploading was still going on. Now im wondering what this option is doing exactly.

Also, in a country where it was dangerous to run a node, which would be ideal setting beside running through Tor? I know that for the network to work you need to contribute yourself, but in a situation where you would want your node to be invisible basically im not sure where the middle ground is. Tor is relatively safe but who knows.

[ranochigo]

Incoming connection doesn't mean that you don't have to request data from other nodes. That option merely means that nodes cannot connect to you, but you will still transfer information to your peers, be it addr, inv, blocks, etc. Connections are bidirectional, so you will still relay blocks, txes to your peers (those that you've initiated a connection to) and your peers can still relay information to you. It is simply impossible for your node to function without any upload activity.

You aren't invisible just by not allowing connections to you.

[pooya87]

Connections are bidirectional, so you will still relay blocks, txes to your peers (those that you've initiated a connection to) and your peers can still relay information to you. It is simply impossible for your node to function without any upload activity.

Technically you don't have to do any of these. There is even an option in the version message called "relay" that could be used to tell other peers you don't want to relay anything such as new (mempool) translations. Your node can also be designed so that it never uploads any data such as blocks, etc. (anything except what is needed for communication).
There is no option for this behavior in reference implementation though.

[NotATether]

I was testing with this option to see what happened if I unchecked this box, I expected that by disabling it no one would be able to reach the node and thus request to download from me wouldn't happen resulting in a flat 0 kb/s line for upload rate, however after a while I saw uploading was still going on. Now im wondering what this option is doing exactly.

There is a small amount of upload bandwidth used when you run a node to get new peers, but this shouldn't concern you unless you know oyu're a target of packet inspection. I don't think Bitcoin Core encrypts its packets so that would be something to look at in the future.

Also, in a country where it was dangerous to run a node, which would be ideal setting beside running through Tor? I know that for the network to work you need to contribute yourself, but in a situation where you would want your node to be invisible basically im not sure where the middle ground is. Tor is relatively safe but who knows.

Spin up a server in a different country and configure Wireguard or OpenVPN as a socks5 proxy between it and your node.

[ranochigo]

There is a small amount of upload bandwidth used when you run a node to get new peers, but this shouldn't concern you unless you know oyu're a target of packet inspection. I don't think Bitcoin Core encrypts its packets so that would be something to look at in the future.

They relay blocks and transactions as well. You can use blocksonly to not receive any transactions that are not in a block yet. Upload bandwidth isn't limited only to getting peers through addr though so it probably would vary quite a bit depending on what your peers request from you.

Encryption can't really do that much, better but not enough. Quite trivial for it to be defeated by traffic analysis as well. It would be far better to just use Tor if you have any concerns about eavesdropping.