diff --git a/include/proto/h1.h b/include/proto/h1.h
index 365d06999..b6c61352e 100644
--- a/include/proto/h1.h
+++ b/include/proto/h1.h
@@ -306,7 +306,7 @@ static inline struct h1m *h1m_init_req(struct h1m *h1m)
 	h1m->state = H1_MSG_RQBEFORE;
 	h1m->next = 0;
 	h1m->status = 0;
-	h1m->flags = 0;
+	h1m->flags = H1_MF_NONE;
 	h1m->curr_len = 0;
 	h1m->body_len = 0;
 	h1m->err_pos = 0;
@@ -320,7 +320,7 @@ static inline struct h1m *h1m_init_res(struct h1m *h1m)
 	h1m->state = H1_MSG_RPBEFORE;
 	h1m->next = 0;
 	h1m->status = 0;
-	h1m->flags = 0;
+	h1m->flags = H1_MF_RESP;
 	h1m->curr_len = 0;
 	h1m->body_len = 0;
 	h1m->err_pos = 0;
diff --git a/include/types/h1.h b/include/types/h1.h
index e410d9d0e..81ea3da9f 100644
--- a/include/types/h1.h
+++ b/include/types/h1.h
@@ -140,6 +140,7 @@ enum h1m_state {
 #define H1_MF_NONE              0x00000000
 #define H1_MF_CLEN              0x00000001 // content-length present
 #define H1_MF_CHNK              0x00000002 // chunk present, exclusive with c-l
+#define H1_MF_RESP              0x00000004 // this message is the response message
 
 
 /* basic HTTP/1 message state for use in parsers */