diff --git a/config.w32 b/config.w32
index 7c407e848a442a1779dd3de501fbdd399c7f6970..8a051e087c5736082cc93903de39cbea37f81c0b 100644
--- a/config.w32
+++ b/config.w32
@@ -287,6 +287,7 @@ if (PHP_GRPC != "no") {
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\dns_resolver_ares.c " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_ev_driver_posix.c " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_wrapper.c " +
+    "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_wrapper_fallback.c " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\native\\dns_resolver.c " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\sockaddr\\sockaddr_resolver.c " +
     "src\\core\\ext\\filters\\load_reporting\\load_reporting.c " +
diff --git a/tools/run_tests/run_tests.py b/tools/run_tests/run_tests.py
index e5632fc8b5e4f58fdce0edb4ec6f73927f224fd0..204ed5c39757078f653af757753f3a5bb99a02d6 100755
--- a/tools/run_tests/run_tests.py
+++ b/tools/run_tests/run_tests.py
@@ -255,8 +255,7 @@ class CLanguage(object):
                  _ROOT + '/src/core/tsi/test_creds/ca.pem',
              'GRPC_POLL_STRATEGY': polling_strategy,
              'GRPC_VERBOSITY': 'DEBUG'}
-        # TODO(zyc): change this back before submission
-        resolver = 'ares';
+        resolver = os.environ.get('GRPC_DNS_RESOLVER', None);
         if resolver:
           env['GRPC_DNS_RESOLVER'] = resolver
         shortname_ext = '' if polling_strategy=='all' else ' GRPC_POLL_STRATEGY=%s' % polling_strategy