I try to create a local private testnet network of ethereum. It seems like when I run two nodes on the same computer(without vm), it uses the same port and ip address although I set different port for each one of them. Is it possible to run a couple of nodes on the same computer, or should I use a vm for that? It also showed me that one of the nodes has 8 peers although I set only 2 nodes. how is it possible?