adding 'listen' param

cli-options/opts.start.json

@@ -98,6 +98,9 @@
   "host": {
     "desc": "Specify a hostname to use"
   },
+  "listen": {
+    "desc": "Specify a hostname bind to (this will prevent binding to all interfaces)"
+  },
   "logLevel": {
     "desc": "Set the logger output level (silent, info or debug)"
   },

lib/async.js

@@ -62,7 +62,7 @@ module.exports = {
             socketPort = bs.options.getIn(["socket", "port"]);
         }
 
-        utils.getPort(socketPort, null, function(err, port) {
+        utils.getPort(bs.options.get("listen", "localhost"), socketPort, null, function(err, port) {
             if (err) {
                 return utils.fail(true, err, bs.cb);
             }
@@ -286,7 +286,18 @@ module.exports = {
                 );
         }
 
-        return ui(uiOpts.toJS(), bs, function(err, ui) {
+        /**
+         * Append the 'listen' option
+         */
+        const opts = uiOpts.update(uiOpts => {
+            const listen = bs.options.get('listen');
+            if (listen) {
+                return uiOpts.set("listen", listen);
+            }
+            return uiOpts;
+        });
+
+        return ui(opts.toJS(), bs, function(err, ui) {
             if (err) {
                 return done(err);
             }

lib/default-config.js

@@ -473,12 +473,13 @@ module.exports = {
 
     /**
      * Specify a host to listen on. Use this if you want to
-     * prevent binding to all interfaces
+     * prevent binding to all interfaces.
+     *
+     * Note: When you specify this option, it overrides the 'host' option
      * @property listen
      * @type String
-     * @default null
+     * @default undefined
      */
-    listen: null,
 
     /**
      * Support environments where dynamic hostnames are not required

lib/server/index.js

@@ -34,7 +34,7 @@ module.exports.plugin = function(bs) {
         /**
          * Listen on the available port
          */
-        bsServer.server.listen(bs.options.get("port"));
+        bsServer.server.listen(bs.options.get("port"), bs.options.get("listen"));
 
         /**
          * Hack to deal with https://github.com/socketio/socket.io/issues/1602#issuecomment-224270022