diff --git a/configure.ac b/configure.ac
index a00782e..db8d6bf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -152,6 +152,11 @@ if test x"$libiscsi_cv_HAVE_LINUX_ISER" = x"yes"; then
 fi
 AM_CONDITIONAL([HAVE_LINUX_ISER], [test $libiscsi_cv_HAVE_LINUX_ISER = yes])
 
+AC_TRY_COMPILE([
+#include <rdma/rdma_cma.h>],
+[return RDMA_OPTION_ID_ACK_TIMEOUT;],
+[AC_DEFINE([HAVE_RDMA_ACK_TIMEOUT],[1],[Define to 1 if you have RDMA ack timeout support])],)
+
 AC_CACHE_CHECK([whether libcunit is available],
                [ac_cv_have_cunit],
                [ac_save_CFLAGS="$CFLAGS"
diff --git a/include/iscsi-private.h b/include/iscsi-private.h
index 3442db6..178669c 100644
--- a/include/iscsi-private.h
+++ b/include/iscsi-private.h
@@ -109,6 +109,8 @@ struct iscsi_context {
 	int tcp_syncnt;
 	int tcp_nonblocking;
 
+	unsigned char rdma_ack_timeout;
+
 	int current_phase;
 	int next_phase;
 #define ISCSI_LOGIN_SECNEG_PHASE_OFFER_CHAP         0
diff --git a/lib/init.c b/lib/init.c
index a120e88..8b2c3df 100644
--- a/lib/init.c
+++ b/lib/init.c
@@ -280,6 +280,10 @@ iscsi_create_context(const char *initiator_name)
 		iscsi_set_bind_interfaces(iscsi,getenv("LIBISCSI_BIND_INTERFACES"));
 	}
 
+	if (getenv("LIBISCSI_RDMA_ACK_TIMEOUT") != NULL) {
+		iscsi->rdma_ack_timeout = (unsigned char)atoi(getenv("LIBISCSI_RDMA_ACK_TIMEOUT"));
+	}
+
 	/* iscsi->smalloc_size is the size for small allocations. this should be
 	   max(ISCSI_HEADER_SIZE, sizeof(struct iscsi_pdu), sizeof(struct iscsi_in_pdu))
 	   rounded up to the next power of 2. */
@@ -617,6 +621,8 @@ iscsi_parse_url(struct iscsi_context *iscsi, const char *url, int full)
 #ifdef HAVE_LINUX_ISER
 			} else if (!strcmp(key, "iser")) {
 				is_iser = 1;
+			} else if (!strcmp(key, "LIBISCSI_RDMA_ACK_TIMEOUT")) {
+				iscsi->rdma_ack_timeout = (unsigned char)atoi(value);
 #endif
 			}
 			tmp = next;
diff --git a/lib/iser.c b/lib/iser.c
index 81f3687..eebb419 100644
--- a/lib/iser.c
+++ b/lib/iser.c
@@ -15,6 +15,10 @@
    along with this program; if not, see <http://www.gnu.org/licenses/>.
 */
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/prctl.h>
@@ -812,6 +816,40 @@ static int iser_create_iser_conn_res(struct iser_conn *iser_conn) {
 	return ret;
 }
 
+void iscsi_set_rdma_ack_timetout(struct iscsi_context *iscsi, unsigned char value)
+{
+	iscsi->rdma_ack_timeout = value;
+	ISCSI_LOG(iscsi, 2, "RDMA ACK TIMEOUT will be set to %d on next rdma qp creation", value);
+}
+
+/*
+ * iser_rdma_set_option() - set rdma options
+ * currently support RDMA ack timeout.
+ * @cma_id:    connection manager id
+ * @iscsi:   iscsi context
+ */
+int iser_rdma_set_option(struct rdma_cm_id *cma_id, struct iscsi_context *iscsi) {
+	int ret = 0;
+	unsigned char timeout = iscsi->rdma_ack_timeout;
+
+	if (timeout) {
+#ifdef HAVE_RDMA_ACK_TIMEOUT
+		/* calculate according to the formula 4.096 * 2^(timeout) usec.
+		   Ex, 8 means 1048.576 usec (0.00104 sec) */
+		ret = rdma_set_option(cma_id, RDMA_OPTION_ID, RDMA_OPTION_ID_ACK_TIMEOUT, &timeout, sizeof(timeout));
+		if (ret) {
+			ISCSI_LOG(iscsi, 1, "failed to set RDMA ACK TIMEOUT: %s", strerror(errno));
+		} else {
+			ISCSI_LOG(iscsi, 3, "RDMA ACK TIMEOUT set to %d", timeout);
+		}
+#else
+		ISCSI_LOG(iscsi, 1, "failed to set RDMA ACK TIMEOUT(%d) for cma_id(%p), please update your kernel&librdmacm", timeout, cma_id);
+#endif
+	}
+
+	return ret;
+}
+
 /*
  * iser_addr_handler() - handles RDMA_CM_EVENT_ADDR_RESOLVED
  *                       event in rdma_cm
@@ -823,6 +861,8 @@ static int iser_addr_handler(struct rdma_cm_id *cma_id) {
 	struct iser_conn *iser_conn = iscsi->opaque;
 	int ret, flags;
 
+	iser_rdma_set_option(cma_id, iscsi);
+
 	ret = rdma_resolve_route(cma_id, 1000);
 	if (ret) {
 		iscsi_set_error(iscsi, "Failed resolving address\n");