diff --git a/include/proto/proto_tcp.h b/include/proto/proto_tcp.h
index a41e025a8..d55f4c544 100644
--- a/include/proto/proto_tcp.h
+++ b/include/proto/proto_tcp.h
@@ -30,7 +30,7 @@
 int tcp_bind_socket(int fd, int flags, struct sockaddr_storage *local, struct sockaddr_storage *remote);
 void tcpv4_add_listener(struct listener *listener);
 void tcpv6_add_listener(struct listener *listener);
-int tcp_connect_server(struct connection *conn, int data);
+int tcp_connect_server(struct connection *conn, int data, int delack);
 int tcp_connect_probe(struct connection *conn);
 int tcp_get_src(int fd, struct sockaddr *sa, socklen_t salen, int dir);
 int tcp_get_dst(int fd, struct sockaddr *sa, socklen_t salen, int dir);
diff --git a/include/proto/stream_interface.h b/include/proto/stream_interface.h
index 7c9595a1f..c8202bcca 100644
--- a/include/proto/stream_interface.h
+++ b/include/proto/stream_interface.h
@@ -111,7 +111,7 @@ static inline int si_connect(struct stream_interface *si)
 	if (unlikely(!si_ctrl(si) || !si_ctrl(si)->connect))
 		return SN_ERR_INTERNAL;
 
-	ret = si_ctrl(si)->connect(si->conn, !channel_is_empty(si->ob));
+	ret = si_ctrl(si)->connect(si->conn, !channel_is_empty(si->ob), !!si->send_proxy_ofs);
 	if (ret != SN_ERR_NONE)
 		return ret;
 
diff --git a/include/types/protocol.h b/include/types/protocol.h
index a8e020ca2..0af2ed8a3 100644
--- a/include/types/protocol.h
+++ b/include/types/protocol.h
@@ -56,7 +56,7 @@ struct protocol {
 	int (*unbind_all)(struct protocol *proto);	/* unbind all bound listeners */
 	int (*enable_all)(struct protocol *proto);	/* enable all bound listeners */
 	int (*disable_all)(struct protocol *proto);	/* disable all bound listeners */
-	int (*connect)(struct connection *, int data);  /* connect function if any */
+	int (*connect)(struct connection *, int data, int delack);  /* connect function if any */
 	int (*get_src)(int fd, struct sockaddr *, socklen_t, int dir); /* syscall used to retrieve src addr */
 	int (*get_dst)(int fd, struct sockaddr *, socklen_t, int dir); /* syscall used to retrieve dst addr */
 
diff --git a/src/checks.c b/src/checks.c
index 7f49547ba..b23fa86bc 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -1318,9 +1318,10 @@ static struct task *process_chk(struct task *t)
 		 *  - SN_ERR_INTERNAL for any other purely internal errors
 		 * Additionnally, in the case of SN_ERR_RESOURCE, an emergency log will be emitted.
 		 * Note that we try to prevent the network stack from sending the ACK during the
-		 * connect() when a pure TCP check is used.
+		 * connect() when a pure TCP check is used (without PROXY protocol).
 		 */
-		ret = s->check.proto->connect(conn, (s->proxy->options2 & PR_O2_CHK_ANY) ? 1 : 2);
+		ret = s->check.proto->connect(conn, s->proxy->options2 & PR_O2_CHK_ANY,
+		                              s->check.send_proxy ? 1 : (s->proxy->options2 & PR_O2_CHK_ANY) ? 0 : 2);
 		conn->flags |= CO_FL_WAKE_DATA;
 		if (s->check.send_proxy)
 			conn->flags |= CO_FL_LOCAL_SPROXY;
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 2b8d148d1..fd9b03d86 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -221,12 +221,13 @@ int tcp_bind_socket(int fd, int flags, struct sockaddr_storage *local, struct so
  * bind addresses are still determined locally (due to the possible need of a
  * source port). conn->target may point either to a valid server or to a backend,
  * depending on conn->target. Only OBJ_TYPE_PROXY and OBJ_TYPE_SERVER are
- * supported. The <data> parameter indicates when non-zero that data will
- * immediately follow the connection and will tune the ACK behaviour after
- * the connect :
- *   - 0 = always send it
- *   - 1 = send it unless the backends has the tcp-smart-connect option
- *   - 2 = never send it
+ * supported. The <data> parameter is a boolean indicating whether there are data
+ * waiting for being sent or not, in order to adjust data write polling and on
+ * some platforms, the ability to avoid an empty initial ACK. The <delack> argument
+ * allows the caller to force using a delayed ACK when establishing the connection :
+ *   - 0 = no delayed ACK unless data are advertised and backend has tcp-smart-connect
+ *   - 1 = delayed ACK if backend has tcp-smart-connect, regardless of data
+ *   - 2 = delayed ACK regardless of backend options
  *
  * It can return one of :
  *  - SN_ERR_NONE if everything's OK
@@ -241,7 +242,7 @@ int tcp_bind_socket(int fd, int flags, struct sockaddr_storage *local, struct so
  * it's invalid and the caller has nothing to do.
  */
 
-int tcp_connect_server(struct connection *conn, int data)
+int tcp_connect_server(struct connection *conn, int data, int delack)
 {
 	int fd;
 	struct server *srv;
@@ -421,9 +422,9 @@ int tcp_connect_server(struct connection *conn, int data)
 #if defined(TCP_QUICKACK)
 	/* disabling tcp quick ack now allows the first request to leave the
 	 * machine with the first ACK. We only do this if there are pending
-	 * data in the buffer or if we plan to close after SYN/ACK (TCP checks).
+	 * data in the buffer.
 	 */
-	if (data == 2 || (data && (be->options2 & PR_O2_SMARTCON)))
+	if (delack == 2 || ((delack || data) && (be->options2 & PR_O2_SMARTCON)))
                 setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, &zero, sizeof(zero));
 #endif