diff --git a/include/types/channel.h b/include/types/channel.h
index 7b4afc83c..6f52372a4 100644
--- a/include/types/channel.h
+++ b/include/types/channel.h
@@ -117,7 +117,8 @@
 #define CF_NEVER_WAIT     0x08000000  /* never wait for sending data (permanent) */
 
 #define CF_WAKE_ONCE      0x10000000  /* pretend there is activity on this channel (one-shoot) */
-/* unused: 0x20000000, 0x40000000, 0x80000000 */
+/* unused: 0x20000000, 0x40000000 */
+#define CF_ISRESP         0x80000000  /* 0 = request channel, 1 = response channel */
 
 /* Masks which define input events for stream analysers */
 #define CF_MASK_ANALYSER  (CF_READ_ATTACHED|CF_READ_ACTIVITY|CF_READ_TIMEOUT|CF_ANA_TIMEOUT|CF_WRITE_ACTIVITY|CF_WAKE_ONCE)
diff --git a/src/hlua.c b/src/hlua.c
index 570c9b4b0..aa6f9954e 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -1908,6 +1908,7 @@ __LJMP static int hlua_socket_new(lua_State *L)
 	 */
 	channel_init(&socket->s->req);
 	channel_init(&socket->s->res);
+	socket->s->res.flags |= CF_ISRESP;
 
 	socket->s->req.prod = &socket->s->si[0];
 	socket->s->req.cons = &socket->s->si[1];
diff --git a/src/peers.c b/src/peers.c
index 805b8d089..708c0196c 100644
--- a/src/peers.c
+++ b/src/peers.c
@@ -1256,6 +1256,8 @@ static struct session *peer_session_create(struct peer *peer, struct peer_sessio
 	s->req.wto = s->be->timeout.server;
 
 	channel_init(&s->res);
+	s->res.flags |= CF_ISRESP;
+
 	s->res.prod = &s->si[1];
 	s->res.cons = &s->si[0];
 
diff --git a/src/session.c b/src/session.c
index a924e8cab..4825cb3c1 100644
--- a/src/session.c
+++ b/src/session.c
@@ -502,6 +502,8 @@ int session_complete(struct session *s)
 	s->req.analyse_exp = TICK_ETERNITY;
 
 	channel_init(&s->res);
+	s->res.flags |= CF_ISRESP;
+
 	s->res.prod = &s->si[1];
 	s->res.cons = &s->si[0];
 	s->res.analysers = 0;