diff --git a/src/mux_h1.c b/src/mux_h1.c
index 3974e53..2de424a 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -593,6 +593,9 @@
 	if (h1s->flags & H1S_F_NOT_FIRST)
 		cs->flags |= CS_FL_NOT_FIRST;
 
+	if (h1s->req.flags & H1_MF_UPG_WEBSOCKET)
+		cs->flags |= CS_FL_WEBSOCKET;
+
 	if (stream_create_from_cs(cs, input) < 0) {
 		TRACE_DEVEL("leaving on stream creation failure", H1_EV_STRM_NEW|H1_EV_STRM_END|H1_EV_STRM_ERR, h1s->h1c->conn, h1s);
 		goto err;
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 278636a..6bf5c14 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -1508,7 +1508,7 @@
  * responsible of it. On error, <input> is unchanged, thus the mux must still
  * take care of it.
  */
-static struct h2s *h2c_frt_stream_new(struct h2c *h2c, int id, struct buffer *input)
+static struct h2s *h2c_frt_stream_new(struct h2c *h2c, int id, struct buffer *input, uint32_t flags)
 {
 	struct session *sess = h2c->conn->owner;
 	struct conn_stream *cs;
@@ -1532,6 +1532,12 @@
 	cs->ctx = h2s;
 	h2c->nb_cs++;
 
+	/* FIXME wrong analogy between ext-connect and websocket, this need to
+	 * be refine.
+	 */
+	if (flags & H2_SF_EXT_CONNECT_RCVD)
+		cs->flags |= CS_FL_WEBSOCKET;
+
 	if (stream_create_from_cs(cs, input) < 0)
 		goto out_free_cs;
 
@@ -2746,7 +2752,7 @@
 	 * Xfer the rxbuf to the stream. On success, the new stream owns the
 	 * rxbuf. On error, it is released here.
 	 */
-	h2s = h2c_frt_stream_new(h2c, h2c->dsi, &rxbuf);
+	h2s = h2c_frt_stream_new(h2c, h2c->dsi, &rxbuf, flags);
 	if (!h2s) {
 		h2s = (struct h2s*)h2_refused_stream;
 		goto send_rst;
diff --git a/src/stream.c b/src/stream.c
index cb2c754..b10800f 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -465,6 +465,9 @@
 			s->si[0].flags |= SI_FL_CLEAN_ABRT;
 		if (cs->conn->mux->flags & MX_FL_HTX)
 			s->flags |= SF_HTX;
+
+		if (cs->flags & CS_FL_WEBSOCKET)
+			s->flags |= SF_WEBSOCKET;
 	}
         /* Set SF_HTX flag for HTTP frontends. */
 	if (sess->fe->mode == PR_MODE_HTTP)