Allow any address we might be listening on

lib/livebook/application.ex

@@ -88,9 +88,7 @@ defmodule Livebook.Application do
           invalid_hostname!("your hostname \"#{hostname}\" does not resolve to an IP address")
 
         {:ok, hostent(h_addrtype: :inet, h_addr_list: addresses)} ->
-          any_loopback? = Enum.any?(addresses, &match?({127, _, _, _}, &1))
+          unless any_loopback?(addresses) or any_if?(addresses) do
-
-          unless any_loopback? do
             invalid_hostname!(
               "your hostname \"#{hostname}\" does not resolve to a loopback address (127.0.0.0/8)"
             )
@@ -102,6 +100,22 @@ defmodule Livebook.Application do
     end
   end
 
+  defp any_loopback?(addresses) do
+    Enum.any?(addresses, &match?({127, _, _, _}, &1))
+  end
+
+  defp any_if?(addresses) do
+    case :inet.getifaddrs() do
+      {:ok, addrs} ->
+        Enum.any?(addrs, fn {_name, flags} ->
+          Enum.any?(flags, fn {key, value} -> key == :addr and value in addresses end)
+        end)
+
+      _ ->
+        false
+    end
+  end
+
   defp invalid_hostname!(prelude) do
     Livebook.Config.abort!("""
     #{prelude}, which indicates something wrong in your OS configuration.