What is meant by getnetworkinfo: networks: reachable = false

What do all the reachable: false's mean under each network? My node is connecting fine to other peers both in and out, I assume via IPv4 (since I didn't configure anything else special). Is my node reachable or not? Or does reachable mean something else in this context?

  "networks": [
    {
      "name": "ipv4",
      "limited": false,
      "reachable": false,
      "proxy": "",
      "proxy_randomize_credentials": false
    }, 
    {
      "name": "ipv6",
      "limited": false,
      "reachable": false,
      "proxy": "",
      "proxy_randomize_credentials": false
    }, 
    {
      "name": "onion",
      "limited": false,
      "reachable": false,
      "proxy": "",
      "proxy_randomize_credentials": false
    }

"reachable": false

is an awkward means of saying the node is on a local network.

What does "Network Unroutable" means?