diff --git a/plugins/ContentFilter/ContentFilterPlugin.py b/plugins/ContentFilter/ContentFilterPlugin.py
index 0902b1c1..4c30a140 100644
--- a/plugins/ContentFilter/ContentFilterPlugin.py
+++ b/plugins/ContentFilter/ContentFilterPlugin.py
@@ -188,7 +188,11 @@ class UiRequestPlugin(object):
         if self.server.site_manager.isDomain(address):
             address = self.server.site_manager.resolveDomain(address)
 
-        address_sha256 = "0x" + hashlib.sha256(address).hexdigest()
+        if address:
+            address_sha256 = "0x" + hashlib.sha256(address).hexdigest()
+        else:
+            address_sha256 = None
+
         if filter_storage.isSiteblocked(address) or filter_storage.isSiteblocked(address_sha256):
             site = self.server.site_manager.get(config.homepage)
             if not extra_headers:
diff --git a/src/Config.py b/src/Config.py
index 7b728cb8..d5a4e735 100644
--- a/src/Config.py
+++ b/src/Config.py
@@ -13,7 +13,7 @@ class Config(object):
 
     def __init__(self, argv):
         self.version = "0.6.4"
-        self.rev = 3747
+        self.rev = 3748
         self.argv = argv
         self.action = None
         self.pending_changes = {}