diff --git a/bin/zuul b/bin/zuul
index c85c84a..46f5b3e 100755
--- a/bin/zuul
+++ b/bin/zuul
@@ -27,6 +27,7 @@ program
 .option('--electron', 'run tests in electron. electron must be installed separately.')
 .option('--tunnel-host <host url>', 'specify a localtunnel server to use for forwarding')
 .option('--sauce-connect [tunnel-identifier]', 'use saucelabs with sauce connect instead of localtunnel. Optionally specify the tunnel-identifier')
+.option('--loopback <host name>', 'hostname to use instead of localhost, to accomodate Safari and Edge with Sauce Connect. Must resolve to 127.0.0.1')
 .option('--server <the server script>', 'specify a server script to be run')
 .option('--list-available-browsers', 'list available browsers and versions')
 .option('--browser-name <browser name>', 'specficy the browser name to test an individual browser')
@@ -52,6 +53,7 @@ var config = {
     prj_dir: process.cwd(),
     tunnel_host: program.tunnelHost,
     sauce_connect: program.sauceConnect,
+    loopback: program.loopback,
     server: program.server,
     concurrency: program.concurrency,
     coverage: program.coverage,
diff --git a/lib/setup.js b/lib/setup.js
index 2dd2baf..2861880 100644
--- a/lib/setup.js
+++ b/lib/setup.js
@@ -35,6 +35,7 @@ function setup_test_instance(opt, cb) {
     function setup(_support_server) {
         support_server = _support_server;
         var config = opt;
+        var loopback = config.loopback || 'localhost';
         var control_port = opt.control_port;
 
         var support_port = undefined;
@@ -65,12 +66,12 @@ function setup_test_instance(opt, cb) {
             return function(req, res) {
                 var args = [].slice.call(arguments);
                 if (is_control_req(req)) {
-                    args.push({ target: 'http://localhost:' + control_port });
+                    args.push({ target: 'http://' + loopback + ':' + control_port });
                     bounce.apply(proxy, args);
                     return;
                 }
 
-                args.push({ target: 'http://localhost:' + support_port }, on_support_server_proxy_done);
+                args.push({ target: 'http://' + loopback + ':' + support_port }, on_support_server_proxy_done);
                 bounce.apply(proxy, args);
             };
         }
@@ -100,7 +101,7 @@ function setup_test_instance(opt, cb) {
             debug('bouncer active on port %d', app_port);
 
             if (!config.tunnel) {
-                return cb(null, 'http://localhost:' + app_port + '/__zuul');
+                return cb(null, 'http://' + loopback + ':' + app_port + '/__zuul');
             }
 
             tunnel.connect(app_port, cb);