diff --git a/tiramisu/option/broadcastoption.py b/tiramisu/option/broadcastoption.py
index c6170dd..abafc45 100644
--- a/tiramisu/option/broadcastoption.py
+++ b/tiramisu/option/broadcastoption.py
@@ -46,7 +46,7 @@ class BroadcastOption(Option):
 
     def _cons_broadcast(self, current_opt, opts, vals, warnings_only):
         if len(vals) != 3:
-            raise ConfigError(_('invalid len for vals'))
+            return ConfigError(_('invalid len for vals'))
         if None in vals:
             return
         broadcast, network, netmask = vals
diff --git a/tiramisu/option/ipoption.py b/tiramisu/option/ipoption.py
index c100494..306e6bb 100644
--- a/tiramisu/option/ipoption.py
+++ b/tiramisu/option/ipoption.py
@@ -84,7 +84,7 @@ class IPOption(Option):
 
     def _cons_in_network(self, current_opt, opts, vals, warnings_only):
         if len(vals) != 3:
-            raise ConfigError(_('invalid len for vals'))
+            return ConfigError(_('invalid len for vals'))
         if None in vals:
             return
         ip, network, netmask = vals