diff --git a/gns3server/config.py b/gns3server/config.py
index 05c0cb96..5d4078c0 100644
--- a/gns3server/config.py
+++ b/gns3server/config.py
@@ -190,6 +190,14 @@ class Config(object):
         :returns: instance of Config
         """
 
-        if not hasattr(Config, "_instance"):
-            Config._instance = Config()
+        if not hasattr(Config, "_instance") or Config._instance is None:
+            Config._instance = Config(files)
         return Config._instance
+
+    @staticmethod
+    def reset():
+        """
+        Reset singleton
+        """
+
+        Config._instance = None
diff --git a/tests/test_main.py b/tests/test_main.py
index cac75afc..8762bcd8 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -35,9 +35,10 @@ def test_locale_check():
     assert locale.getlocale() == ('fr_FR', 'UTF-8')
 
 
-def test_parse_arguments(capsys):
+def test_parse_arguments(capsys, tmpdir):
 
-    config = Config.instance()
+    Config.reset()
+    config = Config.instance(str(tmpdir / "test.cfg"))
     server_config = config.get_section_config("Server")
 
     with pytest.raises(SystemExit):
@@ -70,7 +71,7 @@ def test_parse_arguments(capsys):
     assert "optional arguments" in out
 
     assert main.parse_arguments(["--host", "192.168.1.1"], server_config).host == "192.168.1.1"
-    assert main.parse_arguments([], server_config).host == "127.0.0.1"
+    assert main.parse_arguments([], server_config).host == "0.0.0.0"
     server_config["host"] = "192.168.1.2"
     assert main.parse_arguments(["--host", "192.168.1.1"], server_config).host == "192.168.1.1"
     assert main.parse_arguments([], server_config).host == "192.168.1.2"