diff --git a/include/haproxy/vars-t.h b/include/haproxy/vars-t.h
index 06f2712e1..ab83b4ebe 100644
--- a/include/haproxy/vars-t.h
+++ b/include/haproxy/vars-t.h
@@ -28,6 +28,7 @@
 /* flags used when setting/clearing variables */
 #define VF_UPDATEONLY 0x00000001   // SCOPE_PROC variables are only updated
 #define VF_CREATEONLY 0x00000002   // do nothing if the variable already exists
+#define VF_PERMANENT  0x00000004   // variables known to the config parser
 
 enum vars_scope {
 	SCOPE_SESS = 0,
@@ -54,6 +55,8 @@ struct var_desc {
 struct var {
 	struct list l; /* Used for chaining vars. */
 	const char *name; /* Contains the variable name. */
+	uint flags;       // VF_*
+	/* 32-bit hole here */
 	struct sample_data data; /* data storage. */
 };
 
diff --git a/src/vars.c b/src/vars.c
index 52f19c560..30aff97e8 100644
--- a/src/vars.c
+++ b/src/vars.c
@@ -357,6 +357,7 @@ static int smp_fetch_var(const struct arg *args, struct sample *smp, const char
  *   - VF_UPDATEONLY: if the scope is SCOPE_PROC, the variable may only be
  *     updated but not created.
  *   - VF_CREATEONLY: do nothing if the variable already exists (success).
+ *   - VF_PERMANENT: this flag will be passed to the variable upon creation
  *
  * It returns 0 on failure, non-zero on success.
  */
@@ -408,6 +409,7 @@ static int var_set(const char *name, enum vars_scope scope, struct sample *smp,
 			goto unlock;
 		LIST_APPEND(&vars->head, &var->l);
 		var->name = name;
+		var->flags = flags & VF_PERMANENT;
 	}
 
 	/* Set type. */