diff --git a/lualib-src/lua-cluster.c b/lualib-src/lua-cluster.c
index c4875070..586f74bf 100644
--- a/lualib-src/lua-cluster.c
+++ b/lualib-src/lua-cluster.c
@@ -74,8 +74,9 @@ lpackrequest(lua_State *L) {
 		return luaL_error(L, "Invalid request message");
 	}
 	size_t sz = (size_t)luaL_checkinteger(L,4);
-	int session = luaL_checkinteger(L,2);
+	int session = luaL_optinteger(L,2,1);	// new connection start with 1
 	if (session <= 0) {
+		skynet_free(msg);
 		return luaL_error(L, "Invalid request session %d", session);
 	}
 	int addr_type = lua_type(L,1);
diff --git a/service/clusterd.lua b/service/clusterd.lua
index 12c4c4e7..3805be25 100644
--- a/service/clusterd.lua
+++ b/service/clusterd.lua
@@ -24,7 +24,6 @@ local function open_channel(t, key)
 	}
 	assert(c:connect(true))
 	t[key] = c
-	node_session[key] = 1
 	return c
 end
 
@@ -63,11 +62,11 @@ function command.listen(source, addr, port)
 end
 
 local function send_request(source, node, addr, msg, sz)
-	local request
-	local c = node_channel[node]
 	local session = node_session[node]
 	-- msg is a local pointer, cluster.packrequest will free it
-	request, node_session[node] = cluster.packrequest(addr, session , msg, sz)
+	local request, new_session = cluster.packrequest(addr, session, msg, sz)
+	local c = node_channel[node]
+	node_session[node] = new_session
 
 	return c:request(request, session)
 end