Does mining require a daemon that allows incoming connections (open firewall ports)?

Question

I've noticed that if I don't open the correct ports on my computer and router, and then type status in the daemon, Monero will show 8+0 connections, meaning it has 8 connections where I'm getting data from other nodes, but no connections where nodes are gathering data from me. Basically, I understand that blocking the required ports results in no incoming connections.

My question: is it possible to mine with this 8+0 daemon? And if so, is the mining less efficient, or will the block solution be slower to spread to the P2P network, lessening the chance that my block solution will "win" and end up in the blockchain?

Answer 1

You are confused. The 8+0 does not mean this. The difference between the two types of connections are who initiated it: your daemon, or a peer. Data can flow in both directions, regardless of whether it was initiated locally or by a peer.

This also means that mining does not need incoming connections. It can work as well with or without.

Not allowing incoming connections makes the network fractionally more unstable. If you don't have incoming connections, there are less possible links between nodes, and the "depth" of network interconnectedness is less than it would otherwise be. Push to the extremes and you see it becomes easier to split the network in several parts, since you have less connections to sever.

As a last point, outgoing connections to not need open firewall ports. Incoming connections do. This might have been a mere typo though, but let's add this in case it's a real misconception.

Answer 2

No, you do not.

You might possibly need open ports if you are "running a node" (i.e., you try to run 'monerod'), and try to mine through that node.

If all you want to do is mining, though, I suggest you use a mining pool (see here for a list). In this case you definitely do not need any open incoming ports, since all you need is for your miner to connect to that pool (not the other way around). Check the docs on the pool, they'll point you to miners that work with their pools (and how to run those).