Multinetwork P2P error: "Another tezos node is probably running on one of these addresses. Please choose another RPC port."

Question

When running a multinetwork node, I encountered an error when I started the delphinet node (P2P port 9732, RPC port 8733) after successfully launching a mainnet node (P2P port 9732, RPC port 8732).

tezos-node config init --data-dir ~/tezos-delphinet --network delphinet
tezos-node identity generate --data-dir ~/tezos-delphinet
tezos-node run --data-dir ~/tezos-delphinet 

The error is that I am using the same address:port (localhost:8733), which is not the case:

Sep  4 21:41:16 - node.main: starting the Tezos node (chain = TEZOS_DELPHINET_2020-09-04T07:08:53Z)
Sep  4 21:41:16 - node.main: disabled local peer discovery
Sep  4 21:41:16 - node.main: read identity file (peer_id = idtuoxyz....MvZ)
Sep  4 21:41:16 - main: shell-node initialization: bootstrapping
Sep  4 21:41:16 - p2p.welcome: Cannot accept incoming connections
Sep  4 21:41:16 - p2p.welcome:   Unix error in bind: Address already in use
tezos-node: Error:
              Another tezos node is probably running on one of these addresses (127.0.0.1:8733). Please choose another RPC port.

Answer 1

I went to ~/tezos-delphinet/config.json and edited the default listen-addr to 9733:

{ "data-dir": "/home/user/tezos-delphinet",
  "p2p":
    { "bootstrap-peers":
        [ "delphinet.tezos.co.il", "delphinet.smartpy.io",
          "delphinet.kaml.fr", "13.53.41.201" ], "listen-addr": "[::]:9733" },
  "network": "delphinet" }

So in fact the problem was not the RPC port but the P2P port. I think it's an issue that the error is not indicating the right problem and how to fix it.