diff --git a/lualib/core.lua b/lualib/core.lua
index 76ecd9f6..8c6b0214 100644
--- a/lualib/core.lua
+++ b/lualib/core.lua
@@ -521,7 +521,7 @@ end,
 		log_info("[sys.core] SILLY_UDP fd:", fd, "closed")
 	end
 end,
-[7] = function(signum)				--SILLY_ERROR = 7
+	[7] = function(signum) 				--SILLY_SIGNAL = 7
 	local fn = signal_dispatch[signum]
 	if fn then
 		local t = task_create(fn)
diff --git a/lualib/core/cluster.lua b/lualib/core/cluster.lua
index 91533633..878c1bfa 100644
--- a/lualib/core/cluster.lua
+++ b/lualib/core/cluster.lua
@@ -1,11 +1,11 @@
 local core = require "core"
-local mutex = require "core.sync.mutex"
 local dns = require "core.dns"
 local logger = require "core.logger"
 local np = require "core.netpacket"
 local type = type
 local pairs = pairs
 local assert = assert
+local format = string.format
 local tcp_connect = core.tcp_connect
 local tcp_send = core.tcp_send
 local tcp_close = core.socket_close
@@ -28,51 +28,24 @@ local mt = {
 }
 
 local function connect_wrapper(self)
-	local lock = self.__lock
 	local fdaddr = self.__fdaddr
-	local connecting = self.__connecting
 	return function(addr)
-		local fd = fdaddr[addr]
-		if fd then
-			return fd, "connected"
-		end
-		connecting[addr] = true
-		local l<close> = lock:lock(addr)
-		fd = fdaddr[addr]
-		if fd then
-			return fd, "connected"
-		end
-		while connecting[addr] do
-			local newaddr = addr
-			local name, port = addr:match("([^:]+):(%d+)")
-			if dns.isname(name) then
-				local ip = dns.lookup(name, dns.A)
-				if ip then
-					newaddr = ip .. ":" .. port
-				else
-					newaddr = nil
-					logger.error("[rpc.client] dns lookup fail", name)
-				end
+		local newaddr = addr
+		local name, port = addr:match("([^:]+):(%d+)")
+		if dns.isname(name) then
+			local ip = dns.lookup(name, dns.A)
+			if ip then
+				newaddr = ip .. ":" .. port
+			else
+				return nil, format("dns lookup:%s fail", name)
 			end
-			if newaddr then
-				local fd, errno = tcp_connect(newaddr, self.__event)
-				if fd then
-					if connecting[addr] then
-						connecting[addr] = nil
-						fdaddr[addr] = fd
-						fdaddr[fd] = addr
-						return fd, "ok"
-					else	--already close
-						tcp_close(fd)
-						return nil, "active closed"
-					end
-				else
-					logger.error("[rpc.client] connect fail", addr, errno)
-				end
-			end
-			core.sleep(1000)
-			logger.info("[rpc.client] retry connect:", addr)
 		end
+		local fd, errstr = tcp_connect(newaddr, self.__event)
+		if not fd then
+			return fd, errstr
+		end
+		fdaddr[fd] = addr
+		return fd, "ok"
 	end
 end
 
@@ -82,29 +55,18 @@ local function listen_wrapper(self)
 		if not fd then
 			return fd, errno
 		end
-		self.__fdaddr[addr] = fd
 		self.__fdaddr[fd] = addr
 		return fd, nil
 	end
 end
 
 local function close_wrapper(self)
-	return function(addr)
-		local connecting = self.__connecting
-		if connecting[addr] then
-			connecting[addr] = nil
-			return true, "connecting"
-		end
+	return function(fd)
 		local fdaddr = self.__fdaddr
-		local fd = fdaddr[addr]
-		if not fd then
+		if not fdaddr[fd] then
 			return false, "closed"
 		end
-		if type(addr) == "string" then
-			addr, fd = fd, addr
-		end
 		fdaddr[fd] = nil
-		fdaddr[addr] = nil
 		core.socket_close(fd)
 		return true, "connected"
 	end
@@ -125,7 +87,6 @@ local function init_event(self, conf)
 	local EVENT = {}
 	function EVENT.accept(fd, _, addr)
 		fdaddr[fd] = addr
-		fdaddr[addr] = fd
 		local ok, err = pcall(accept, fd, addr)
 		if not ok then
 			logger.error("[rpc.server] EVENT.accept", err)
@@ -135,9 +96,7 @@ local function init_event(self, conf)
 	end
 
 	function EVENT.close(fd, errno)
-		local addr = fdaddr[fd]
 		fdaddr[fd] = nil
-		fdaddr[addr] = nil
 		local ok, err = pcall(close, fd, errno)
 		if not ok then
 			logger.error("[rpc.server] EVENT.close", err)
@@ -272,19 +231,17 @@ local M = {}
 function M.new(conf)
 	---@class core.cluster
 	local obj = {
-		__lock = mutex:new(),
 		__ctx = np.create(),
 		__fdaddr = {},
 		__waitpool = {},
 		__waitcmd = {},
 		__waitfor = nil,
 		__event = nil,
-		__connecting = {},
 		---@type async fun(addr:string):number?,string?
 		connect = nil,
 		---@type fun(addr:string, backlog?:number):number?,string?
 		listen = nil,
-		---@type fun(addr:string):boolean,string?
+		---@type fun(addr:string|integer):boolean,string?
 		close = nil,
 		---@type fun(fd:number, cmd:string, obj:any):any?,string?
 		call = nil,
diff --git a/test/testrpc.lua b/test/testrpc.lua
index e0cb0d1e..c9536a40 100644
--- a/test/testrpc.lua
+++ b/test/testrpc.lua
@@ -87,7 +87,7 @@ local server = cluster.new {
 	end,
 }
 
-server.listen(":8989")
+local listen_fd = server.listen(":8989")
 local client_fd
 local client = cluster.new {
 	timeout = 1000,
@@ -182,8 +182,8 @@ end
 
 client_part()
 server_part()
-client.close("127.0.0.1:8989")
-server.close(":8989")
-server.close(accept_addr)
+client.close(client_fd)
+server.close(listen_fd)
+server.close(accept_fd)
 testaux.asserteq(next(client.__fdaddr), nil, "client fdaddr empty")
 testaux.asserteq(next(server.__fdaddr), nil, "client fdaddr empty")