diff --git a/ospfd/ChangeLog b/ospfd/ChangeLog
index 7486b07..e3805c8 100644
--- a/ospfd/ChangeLog
+++ b/ospfd/ChangeLog
@@ -3,6 +3,10 @@
 	* ospf_nsm.c: (nsm_should_adj) New function, just consolidate the
 	  10.4 adjacency check from nsm_twoway_received/nsm_adj_ok.
 	  (nsm_twoway_received/nsm_adj_ok) Use former.
+	  (ospf_nsm_event) Don't allow action functions to change
+	  next_state if the NSM tables do not indicate next_state is
+	  conditional, log warning if one tries - existing code
+	  appears fine though.
 
 2006-06-30 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
 
diff --git a/ospfd/ospf_nsm.c b/ospfd/ospf_nsm.c
index c5a5536..73ed088 100644
--- a/ospfd/ospf_nsm.c
+++ b/ospfd/ospf_nsm.c
@@ -878,6 +878,22 @@
 
   if (! next_state)
     next_state = NSM [nbr->state][event].next_state;
+  else if (NSM [nbr->state][event].next_state != NSM_DependUpon)
+    {
+      /* There's a mismatch between the FSM tables and what an FSM
+       * action/state-change function returned. State changes which
+       * do not have conditional/DependUpon next-states should not
+       * try set next_state.
+       */
+      zlog_warn ("NSM[%s:%s]: %s (%s): "
+                 "Warning: action tried to change next_state to %s",
+                 IF_NAME (oi), inet_ntoa (nbr->router_id),
+                 LOOKUP (ospf_nsm_state_msg, nbr->state),
+                 ospf_nsm_event_str [event],
+                 LOOKUP (ospf_nsm_state_msg, next_state));
+      
+      next_state = NSM [nbr->state][event].next_state;
+    }
 
   if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
     zlog_debug ("NSM[%s:%s]: %s (%s)", IF_NAME (oi),