diff --git a/filter-rules.py b/filter-rules.py
index b831675..e90dd81 100644
--- a/filter-rules.py
+++ b/filter-rules.py
@@ -151,6 +151,7 @@ def filter_message(self, message):
         headers.append(h)
 
     # junk messages from blocked domains
+    is_spam = False
     for domain in BLOCK_DOMAINS:
         if domain in normalized_from:
             is_spam = True