The Coin network
Coin runs on a network of nodes: ordinary computers that each keep a copy of the blockchain and pass new payments and blocks along. There's no central server, and nobody in charge.
How nodes find each other
Every node keeps connections to a handful of others, called peers. A brand-new node finds its first peers through the seed node, then learns about more nodes from the peers it meets. From then on, it remembers them.
The seed node
New nodes can always find the network through seed.coinnet.org:38880. It's a starting point, not a boss: once your node has peers, it doesn't depend on the seed node at all.
First the stem: your payment hops quietly from one random node to the next. Then the fluff: a node that isn't yours broadcasts it to everyone. Watching the network, it looks like it started somewhere else.
Hiding where a payment came from
The blockchain never records IP addresses, but a watcher with many nodes could try to spot which node a payment appeared from first. Dandelion++ spoils that by passing each new payment along a short, random chain of nodes before it's broadcast. For even more cover, run your node over Tor.
Blocks
Miners collect new payments into blocks, about one every two minutes. Every node checks every block, and the difficulty adjusts by itself to keep that pace as miners come and go.
Ports
| Port | Used for | Open it? |
|---|---|---|
| 38880 TCP | Peer-to-peer: talking to other nodes | Optional. Opening it lets new nodes connect to yours. |
| 38881 TCP | Node RPC: how your wallet talks to your node | No. Keep it on your own computer. |