1 files changed, 5 insertions, 0 deletions
diff --git a/conf/cf-lex.l b/conf/cf-lex.l
index 95237215..8dc0ac89 100644
--- a/conf/cf-lex.l
+++ b/conf/cf-lex.l
@@ -559,6 +559,9 @@ static inline void cf_swap_soft_scope(struct config *conf);
 static struct symbol *
 cf_new_symbol(struct sym_scope *scope, pool *p, struct linpool *lp, const byte *c)
 {
+  if (scope->readonly)
+    cf_error("Unknown symbol %s", c);
+
   struct symbol *s;
 
   uint l = strlen(c);
@@ -712,6 +715,8 @@ cf_lex_init(int is_cli, struct config *c)
       sym->class = SYM_KEYWORD;
       sym->keyword = k;
     }
+
+    global_root_scope->readonly = 1;
   }
 
   ifs_head = ifs = push_ifs(NULL);