diff --git a/swift/proxy/server.py b/swift/proxy/server.py
index 5e34b65ff2..58deb94070 100644
--- a/swift/proxy/server.py
+++ b/swift/proxy/server.py
@@ -87,6 +87,9 @@ def _label_for_policy(policy):
     return '(default)'
 
 
+VALID_SORTING_METHODS = ('shuffle', 'timing', 'affinity')
+
+
 class ProxyOverrideOptions(object):
     """
     Encapsulates proxy server options that may be overridden e.g. for
@@ -100,6 +103,11 @@ class ProxyOverrideOptions(object):
             return override_conf.get(key, base_conf.get(key, default))
 
         self.sorting_method = get('sorting_method', 'shuffle').lower()
+        if self.sorting_method not in VALID_SORTING_METHODS:
+            raise ValueError(
+                'Invalid sorting_method value; must be one of %s, not %r' % (
+                    ', '.join(VALID_SORTING_METHODS), self.sorting_method))
+
         self.read_affinity = get('read_affinity', '')
         try:
             self.read_affinity_sort_key = affinity_key_function(
diff --git a/test/unit/proxy/test_server.py b/test/unit/proxy/test_server.py
index 177da4f738..22b312fbbe 100644
--- a/test/unit/proxy/test_server.py
+++ b/test/unit/proxy/test_server.py
@@ -1739,6 +1739,35 @@ class TestProxyServerConfigLoading(unittest.TestCase):
         app = self._write_conf_and_load_app(conf_sections)
         self._check_policy_options(app, exp_options, {})
 
+    def test_per_policy_conf_invalid_sorting_method_value(self):
+        def do_test(conf_sections, scope):
+            with self.assertRaises(ValueError) as cm:
+                self._write_conf_and_load_app(conf_sections)
+            self.assertEqual(
+                'Invalid sorting_method value; must be one of shuffle, '
+                "timing, affinity, not 'broken' for %s" % scope,
+                cm.exception.message)
+
+        conf_sections = """
+        [app:proxy-server]
+        use = egg:swift#proxy
+        sorting_method = shuffle
+
+        [proxy-server:policy:0]
+        sorting_method = broken
+        """
+        do_test(conf_sections, 'policy 0 (nulo)')
+
+        conf_sections = """
+        [app:proxy-server]
+        use = egg:swift#proxy
+        sorting_method = broken
+
+        [proxy-server:policy:0]
+        sorting_method = shuffle
+        """
+        do_test(conf_sections, '(default)')
+
     def test_per_policy_conf_invalid_read_affinity_value(self):
         def do_test(conf_sections, label):
             with self.assertRaises(ValueError) as cm: