diff --git a/tiramisu/option.py b/tiramisu/option.py
index 5c8bbda..8a1804c 100644
--- a/tiramisu/option.py
+++ b/tiramisu/option.py
@@ -492,6 +492,8 @@ class IPOption(Option):
     def _validate(self, value):
         try:
             ip = IP('{0}/32'.format(value))
+            if ip.iptype() == 'RESERVED':
+                return False
             if self._only_private:
                 return ip.iptype() == 'PRIVATE'
             return True
@@ -576,7 +578,9 @@ class NetworkOption(Option):
 
     def _validate(self, value):
         try:
-            IP(value)
+            ip = IP(value)
+            if ip.iptype() == 'RESERVED':
+                return False
             return True
         except ValueError:
             return False