=== trac/Ticket.py
==================================================================
--- trac/Ticket.py	(revision 6282)
+++ trac/Ticket.py	(local)
@@ -339,6 +339,9 @@
     template_name = 'ticket.cs'
 
     def save_changes (self, id):
+        if self.req.authname == 'anonymous' and self.args.get('comment').find('dynu.net') != -1:
+            raise TracError("Blocking spam")
+
         self.perm.assert_permission (perm.TICKET_MODIFY)
         ticket = Ticket(self.db, id)