diff --git a/conf/conf.go b/conf/conf.go
index 5cf08b9..97588ce 100644
--- a/conf/conf.go
+++ b/conf/conf.go
@@ -1,15 +1,9 @@
 package conf
 
 import (
-	"context"
 	"flag"
 	"os"
-	"os/exec"
-	"runtime"
 	"strconv"
-	"time"
-
-	"github.com/pkg/errors"
 
 	"github.com/golang/glog"
 	toml "github.com/pelletier/go-toml"
@@ -41,6 +35,9 @@ var Conf = struct {
 
 func init() {
 	initArgs()
+	if Conf.VersionOnly {
+		return
+	}
 
 	if _, err := os.Stat(Conf.ConfigFile); os.IsNotExist(err) {
 		glog.Warningln("no config file has been load:", Conf.ConfigFile)
@@ -77,19 +74,7 @@ var refreshFns = []func() (string, error){
 	func() (string, error) {
 		action := "clear dns cache"
 		if Conf.ClearDNSCache != "" {
-			ctx, cancel := context.WithTimeout(context.TODO(), 5*time.Second)
-			defer cancel()
-
-			switch runtime.GOOS {
-			case "windows":
-				if out, err := exec.CommandContext(ctx, "cmd", "/c", Conf.ClearDNSCache).CombinedOutput(); err != nil {
-					return action, errors.Wrapf(err, "cmd: %s, output: %s, error", Conf.ClearDNSCache, out)
-				}
-			default:
-				if out, err := exec.CommandContext(ctx, "sh", "-c", Conf.ClearDNSCache).CombinedOutput(); err != nil {
-					return action, errors.Wrapf(err, "cmd: %s, output: %s, error", Conf.ClearDNSCache, out)
-				}
-			}
+			return action, execute(Conf.ClearDNSCache)
 		}
 		return action, nil
 	},
diff --git a/conf/conf_other.go b/conf/conf_other.go
index 43eb08d..001cfd6 100644
--- a/conf/conf_other.go
+++ b/conf/conf_other.go
@@ -3,11 +3,15 @@
 package conf
 
 import (
+	"context"
 	"flag"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strings"
+	"time"
 
+	"github.com/pkg/errors"
 	"github.com/wweir/sower/dns"
 	"github.com/wweir/sower/proxy/shadow"
 	"github.com/wweir/sower/proxy/transport"
@@ -31,3 +35,11 @@ func initArgs() {
 		flag.Parse()
 	}
 }
+
+func execute(cmd string) error {
+	ctx, cancel := context.WithTimeout(context.TODO(), 5*time.Second)
+	defer cancel()
+
+	out, err := exec.CommandContext(ctx, "sh", "-c", Conf.ClearDNSCache).CombinedOutput()
+	return errors.Wrapf(err, "cmd: %s, output: %s, error", Conf.ClearDNSCache, out)
+}
diff --git a/conf/conf_windows.go b/conf/conf_windows.go
index f9c08c2..d7cba50 100644
--- a/conf/conf_windows.go
+++ b/conf/conf_windows.go
@@ -3,14 +3,18 @@
 package conf
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strings"
+	"syscall"
 	"time"
 
 	"github.com/golang/glog"
+	"github.com/pkg/errors"
 	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/svc"
 	"golang.org/x/sys/windows/svc/eventlog"
@@ -146,3 +150,28 @@ func (m *myservice) Execute(args []string, r <-chan svc.ChangeRequest, changes c
 		}
 	}
 }
+
+func execute(cmd string) error {
+	ctx, cancel := context.WithTimeout(context.TODO(), 5*time.Second)
+	defer cancel()
+
+	var cmds []string
+	for _, cmd := range strings.Split(Conf.ClearDNSCache, " ") {
+		if cmd == "" {
+			continue
+		}
+		if strings.HasPrefix(cmd, "/") {
+			cmd = strings.Replace(cmd, "/", "-", 1)
+		}
+		cmds = append(cmds, cmd)
+	}
+
+	if len(cmds) != 0 {
+		return nil
+	}
+
+	command := exec.CommandContext(ctx, cmds[0], cmds[1:]...)
+	command.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
+	out, err := command.CombinedOutput()
+	return errors.Wrapf(err, "cmd: %s, output: %s, error", Conf.ClearDNSCache, out)
+}
diff --git a/conf/sower.toml b/conf/sower.toml
index 9361884..39f9ab7 100644
--- a/conf/sower.toml
+++ b/conf/sower.toml
@@ -4,9 +4,9 @@ password="12345678"
 server_port="5533"
 # server_addr="remote-server:5533" # replce it to remote server
 http_proxy=":8080"               # eg: 192.168.0.2:8080
-dns_server="114.114.114.114"     # Keep empty for dynamic setting from net env
+dns_server=""     # Keep empty for dynamic setting from net env
 client_ip="127.0.0.1"            # listen the IP, dns target is the IP
-# clear_dns_cache="pkill mDNSResponder"   # Windows: "ipconfig /flushdnss"
+# clear_dns_cache="pkill mDNSResponder || true"   # Windows: "ipconfig /flushdnss"
 suggest_level="SPEEDUP"          # DISABLE, BLOCK, SPEEDUP
 blocklist=[
     "**.google.*", # google
diff --git a/main.go b/main.go
index 156ad80..d1120d7 100644
--- a/main.go
+++ b/main.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"net"
 
@@ -16,7 +17,8 @@ var version, date string
 func main() {
 	cfg := &conf.Conf
 	if cfg.VersionOnly {
-		fmt.Printf("Version: %s %s  config: %v", version, date, cfg)
+		config, _ := json.MarshalIndent(cfg, "", "\t")
+		fmt.Printf("Version:\n\t%s %s\nConfig:\n%s", version, date, config)
 		return
 	}
 	glog.Infof("Starting sower(%s %s): %v", version, date, cfg)