diff --git a/overviewer_core/configParser.py b/overviewer_core/configParser.py
index ee47d01..78b5f84 100644
--- a/overviewer_core/configParser.py
+++ b/overviewer_core/configParser.py
@@ -68,7 +68,7 @@ class MultiWorldParser(object):
         """Validate and return the configuration"""
         # Okay, this is okay, isn't it? We're going to create the validation
         # routine right here, right now. I hope this works!
-        validator = settingsValidators.make_configDictValidator(self._settings)
+        validator = settingsValidators.make_configDictValidator(self._settings, ignore_undefined=True)
         # Woah. What just happened? No. WAIT, WHAT ARE YOU...
         validated_config = validator(self._config_state)
         # WHAT HAVE YOU DONE?
diff --git a/overviewer_core/settingsValidators.py b/overviewer_core/settingsValidators.py
index 126c634..3426919 100644
--- a/overviewer_core/settingsValidators.py
+++ b/overviewer_core/settingsValidators.py
@@ -148,7 +148,7 @@ def make_dictValidator(keyvalidator, valuevalidator):
         return newd
     return v
 
-def make_configDictValidator(config):
+def make_configDictValidator(config, ignore_undefined=False):
     """Okay, stay with me here, this may get confusing. This function returns a
     validator that validates a "configdict". This is a term I just made up to
     refer to a dict that holds config information: keys are strings and values
@@ -160,6 +160,10 @@ def make_configDictValidator(config):
 
     I hope that makes sense.
 
+    ignore_undefined, if True, will ignore any items in the dict to be
+    validated which don't have a corresponding definition in the config.
+    Otherwise, undefined entries will raise an error.
+
     """
     def configDictValidator(d):
         newdict = {}
@@ -177,9 +181,10 @@ def make_configDictValidator(config):
 
         # Now that all the defined keys have been accounted for, check to make
         # sure any unauthorized keys were not specified.
-        for key in d.iterkeys():
-            if key not in config:
-                raise ValidationException("'%s' is not a configuration item" % key)
+        if not ignore_undefined:
+            for key in d.iterkeys():
+                if key not in config:
+                    raise ValidationException("'%s' is not a configuration item" % key)
         return newdict
 
     return configDictValidator