diff --git a/src/main/java/com/github/shadowsocks/System.java b/src/main/java/com/github/shadowsocks/System.java
index 47b10ed6..cc89e624 100755
--- a/src/main/java/com/github/shadowsocks/System.java
+++ b/src/main/java/com/github/shadowsocks/System.java
@@ -43,7 +43,7 @@ public class System {
     java.lang.System.loadLibrary("system");
   }
 
-  public static native void exec(String cmd);
+  public static native int exec(String cmd);
   public static native String getABI();
   public static native int sendfd(int fd);
   public static native void jniclose(int fd);
diff --git a/src/main/jni/Android.mk b/src/main/jni/Android.mk
index 43614f65..a4034411 100755
--- a/src/main/jni/Android.mk
+++ b/src/main/jni/Android.mk
@@ -214,7 +214,7 @@ include $(BUILD_STATIC_LIBRARY)
 
 include $(CLEAR_VARS)
 
-REDSOCKS_SOURCES := base.c dnstc.c http-connect.c \
+REDSOCKS_SOURCES := base.c http-connect.c \
 	log.c md5.c socks5.c \
 	base64.c http-auth.c http-relay.c main.c \
 	parser.c redsocks.c socks4.c utils.c
@@ -223,7 +223,8 @@ LOCAL_STATIC_LIBRARIES := libevent
 
 LOCAL_MODULE := redsocks
 LOCAL_SRC_FILES := $(addprefix redsocks/, $(REDSOCKS_SOURCES)) 
-LOCAL_CFLAGS := -O2 -std=gnu99 -I$(LOCAL_PATH)/redsocks \
+LOCAL_CFLAGS := -O2 -std=gnu99 -DUSE_IPTABLES \
+	-I$(LOCAL_PATH)/redsocks \
 	-I$(LOCAL_PATH)/libevent/include \
 	-I$(LOCAL_PATH)/libevent
 
diff --git a/src/main/jni/redsocks b/src/main/jni/redsocks
index 65d039c7..76348e93 160000
--- a/src/main/jni/redsocks
+++ b/src/main/jni/redsocks
@@ -1 +1 @@
-Subproject commit 65d039c7b302510188dc7b3d765a206c3980db51
+Subproject commit 76348e933a3a15176fdb54616d04bc6fdd3c8e0b
diff --git a/src/main/jni/system.cpp b/src/main/jni/system.cpp
index 39cfc1e4..1252fb0a 100644
--- a/src/main/jni/system.cpp
+++ b/src/main/jni/system.cpp
@@ -37,10 +37,27 @@ jstring Java_com_github_shadowsocks_system_getabi(JNIEnv *env, jobject thiz) {
   return env->NewStringUTF(abi);
 }
 
-void Java_com_github_shadowsocks_system_exec(JNIEnv *env, jobject thiz, jstring cmd) {
-    const char *str  = env->GetStringUTFChars(cmd, 0);
-    system(str);
-    env->ReleaseStringUTFChars(cmd, str);
+jint Java_com_github_shadowsocks_system_exec(JNIEnv *env, jobject thiz, jstring cmd) {
+    const char *cmd_str  = env->GetStringUTFChars(cmd, 0);
+
+    pid_t pid;
+
+    /*  Fork off the parent process */
+    pid = fork();
+    if (pid < 0) {
+        env->ReleaseStringUTFChars(cmd, cmd_str);
+        return -1;
+    }
+
+    if (pid > 0) {
+        env->ReleaseStringUTFChars(cmd, cmd_str);
+        return pid;
+    }
+
+    execl("/system/bin/sh", "sh", "-c", cmd_str, NULL);
+    env->ReleaseStringUTFChars(cmd, cmd_str);
+
+    return 1;
 }
 
 void Java_com_github_shadowsocks_system_jniclose(JNIEnv *env, jobject thiz, jint fd) {
@@ -83,7 +100,7 @@ static JNINativeMethod method_table[] = {
         (void*) Java_com_github_shadowsocks_system_jniclose },
     { "sendfd", "(I)I",
         (void*) Java_com_github_shadowsocks_system_sendfd },
-    { "exec", "(Ljava/lang/String;)V",
+    { "exec", "(Ljava/lang/String;)I",
         (void*) Java_com_github_shadowsocks_system_exec },
     { "getABI", "()Ljava/lang/String;",
         (void*) Java_com_github_shadowsocks_system_getabi }
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala
index 54fdfa3d..52e11c9d 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala
@@ -75,6 +75,11 @@ class ShadowsocksNatService extends Service with BaseService {
   var apps: Array[ProxiedApp] = null
   val myUid = Process.myUid()
 
+  var sslocalPid: Int = 0;
+  var sstunnelPid: Int = 0;
+  var redsocksPid: Int = 0;
+  var pdnsdPid: Int = 0;
+
   private val dnsAddressCache = new SparseArray[String]
 
   def getNetId(network: Network): Int = {
@@ -184,8 +189,7 @@ class ShadowsocksNatService extends Service with BaseService {
     cmd += (Path.BASE + "ss-local"
           , "-b" , "127.0.0.1"
           , "-t" , "600"
-          , "-c" , Path.BASE + "ss-local-nat.conf"
-          , "-f" , Path.BASE + "ss-local-nat.pid")
+          , "-c" , Path.BASE + "ss-local-nat.conf")
 
     if (config.isAuth) cmd += "-A"
 
@@ -195,7 +199,7 @@ class ShadowsocksNatService extends Service with BaseService {
     }
 
     if (BuildConfig.DEBUG) Log.d(TAG, cmd.mkString(" "))
-    Console.runCommand(cmd.mkString(" "))
+    sslocalPid = System.exec(cmd.mkString(" "))
   }
 
   def startTunnel() {
@@ -212,8 +216,7 @@ class ShadowsocksNatService extends Service with BaseService {
         , "-t" , "10"
         , "-b" , "127.0.0.1"
         , "-L" , "8.8.8.8:53"
-        , "-c" , Path.BASE + "ss-tunnel-nat.conf"
-        , "-f" , Path.BASE + "ss-tunnel-nat.pid")
+        , "-c" , Path.BASE + "ss-tunnel-nat.conf")
 
       cmd += ("-l" , "8153")
 
@@ -221,7 +224,7 @@ class ShadowsocksNatService extends Service with BaseService {
 
       if (BuildConfig.DEBUG) Log.d(TAG, cmd.mkString(" "))
 
-      Console.runCommand(cmd.mkString(" "))
+     sstunnelPid =  System.exec(cmd.mkString(" "))
 
     } else {
       val conf = ConfigUtils
@@ -237,13 +240,13 @@ class ShadowsocksNatService extends Service with BaseService {
         , "-b" , "127.0.0.1"
         , "-l" , "8163"
         , "-L" , "8.8.8.8:53"
-        , "-c" , Path.BASE + "ss-tunnel-nat.conf"
-        , "-f" , Path.BASE + "ss-tunnel-nat.pid")
+        , "-c" , Path.BASE + "ss-tunnel-nat.conf")
 
       if (config.isAuth) cmdBuf += "-A"
 
       if (BuildConfig.DEBUG) Log.d(TAG, cmdBuf.mkString(" "))
-      Console.runCommand(cmdBuf.mkString(" "))
+
+      sstunnelPid = System.exec(cmdBuf.mkString(" "))
     }
   }
 
@@ -253,10 +256,10 @@ class ShadowsocksNatService extends Service with BaseService {
       val reject = ConfigUtils.getRejectList(getContext)
       val blackList = ConfigUtils.getBlackList(getContext)
       ConfigUtils.PDNSD_DIRECT.formatLocal(Locale.ENGLISH, "127.0.0.1", 8153,
-        Path.BASE + "pdnsd-nat.pid", reject, blackList, 8163, "")
+        reject, blackList, 8163, "")
     } else {
       ConfigUtils.PDNSD_LOCAL.formatLocal(Locale.ENGLISH, "127.0.0.1", 8153,
-        Path.BASE + "pdnsd-nat.pid", 8163, "")
+        8163, "")
     }
 
     ConfigUtils.printToFile(new File(Path.BASE + "pdnsd-nat.conf"))(p => {
@@ -266,7 +269,7 @@ class ShadowsocksNatService extends Service with BaseService {
 
     if (BuildConfig.DEBUG) Log.d(TAG, cmd)
 
-    Console.runCommand(cmd)
+    pdnsdPid = System.exec(cmd)
 
   }
 
@@ -284,14 +287,14 @@ class ShadowsocksNatService extends Service with BaseService {
 
   def startRedsocksDaemon() {
     val conf = ConfigUtils.REDSOCKS.formatLocal(Locale.ENGLISH, config.localPort)
-    val cmd = Path.BASE + "redsocks -p %sredsocks-nat.pid -c %sredsocks-nat.conf"
+    val cmd = Path.BASE + "redsocks -c %sredsocks-nat.conf"
       .formatLocal(Locale.ENGLISH, Path.BASE, Path.BASE)
     ConfigUtils.printToFile(new File(Path.BASE + "redsocks-nat.conf"))(p => {
       p.println(conf)
     })
 
     if (BuildConfig.DEBUG) Log.d(TAG, cmd)
-    Console.runCommand(cmd)
+    redsocksPid = System.exec(cmd)
   }
 
   /** Called when the activity is first created. */
@@ -348,27 +351,27 @@ class ShadowsocksNatService extends Service with BaseService {
   }
 
   def killProcesses() {
-    val cmd = new ArrayBuffer[String]()
-
-    for (task <- Array("ss-local", "ss-tunnel", "pdnsd", "redsocks")) {
-      cmd.append("chmod 666 %s%s-nat.pid".formatLocal(Locale.ENGLISH, Path.BASE, task))
+    try {
+      Process.killProcess(sslocalPid)
+    } catch {
+      case e: Throwable => Log.e(TAG, "unable to kill ss-local")
     }
-    Console.runRootCommand(cmd.toArray)
-    cmd.clear()
-
-    for (task <- Array("ss-local", "ss-tunnel", "pdnsd", "redsocks")) {
-      try {
-        val pid = scala.io.Source.fromFile(Path.BASE + task + "-nat.pid").mkString.trim.toInt
-        cmd.append("kill -9 %d".formatLocal(Locale.ENGLISH, pid))
-        Process.killProcess(pid)
-      } catch {
-        case e: Throwable => Log.e(TAG, "unable to kill " + task)
-      }
-      cmd.append("rm -f %s%s-nat.pid".formatLocal(Locale.ENGLISH, Path.BASE, task))
-      cmd.append("rm -f %s%s-nat.conf".formatLocal(Locale.ENGLISH, Path.BASE, task))
+    try {
+      Process.killProcess(sstunnelPid)
+    } catch {
+      case e: Throwable => Log.e(TAG, "unable to kill ss-tunnel")
+    }
+    try {
+      Process.killProcess(redsocksPid)
+    } catch {
+      case e: Throwable => Log.e(TAG, "unable to kill redsocks")
+    }
+    try {
+      Process.killProcess(pdnsdPid)
+    } catch {
+      case e: Throwable => Log.e(TAG, "unable to kill pdnsd")
     }
 
-    Console.runRootCommand(cmd.toArray)
     Console.runRootCommand(Utils.getIptables + " -t nat -F OUTPUT")
   }
 
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
index 0b454a62..8b78ba7c 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
@@ -71,6 +71,11 @@ class ShadowsocksVpnService extends VpnService with BaseService {
   var vpnThread: ShadowsocksVpnThread = null
   var closeReceiver: BroadcastReceiver = null
 
+  var sslocalPid: Int = 0;
+  var sstunnelPid: Int = 0;
+  var tun2socksPid: Int = 0;
+  var pdnsdPid: Int = 0;
+
   def isByass(net: SubnetUtils): Boolean = {
     val info = net.getInfo
     info.isInRange(config.proxy)
@@ -188,13 +193,25 @@ class ShadowsocksVpnService extends VpnService with BaseService {
   }
 
   def killProcesses() {
-    for (task <- Array("ss-local", "ss-tunnel", "pdnsd", "tun2socks")) {
-      try {
-        val pid = scala.io.Source.fromFile(Path.BASE + task + "-vpn.pid").mkString.trim.toInt
-        Process.killProcess(pid)
-      } catch {
-        case e: Throwable => Log.e(TAG, "unable to kill " + task)
-      }
+    try {
+      Process.killProcess(sslocalPid)
+    } catch {
+      case e: Throwable => Log.e(TAG, "unable to kill ss-local")
+    }
+    try {
+      Process.killProcess(sstunnelPid)
+    } catch {
+      case e: Throwable => Log.e(TAG, "unable to kill ss-tunnel")
+    }
+    try {
+      Process.killProcess(tun2socksPid)
+    } catch {
+      case e: Throwable => Log.e(TAG, "unable to kill tun2socks")
+    }
+    try {
+      Process.killProcess(pdnsdPid)
+    } catch {
+      case e: Throwable => Log.e(TAG, "unable to kill pdnsd")
     }
   }
 
@@ -316,8 +333,7 @@ class ShadowsocksVpnService extends VpnService with BaseService {
     cmd += (Path.BASE + "ss-local", "-V", "-u"
       , "-b", "127.0.0.1"
       , "-t", "600"
-      , "-c", Path.BASE + "ss-local-vpn.conf"
-      , "-f", Path.BASE + "ss-local-vpn.pid")
+      , "-c", Path.BASE + "ss-local-vpn.conf")
 
     if (config.isAuth) cmd += "-A"
 
@@ -327,7 +343,7 @@ class ShadowsocksVpnService extends VpnService with BaseService {
     }
 
     if (BuildConfig.DEBUG) Log.d(TAG, cmd.mkString(" "))
-    Console.runCommand(cmd.mkString(" "))
+    sslocalPid = System.exec(cmd.mkString(" "))
   }
 
   def startDnsTunnel() = {
@@ -345,13 +361,12 @@ class ShadowsocksVpnService extends VpnService with BaseService {
       , "-b", "127.0.0.1"
       , "-l", "8163"
       , "-L", "8.8.8.8:53"
-      , "-c", Path.BASE + "ss-tunnel-vpn.conf"
-      , "-f", Path.BASE + "ss-tunnel-vpn.pid")
+      , "-c", Path.BASE + "ss-tunnel-vpn.conf")
 
     if (config.isAuth) cmd += "-A"
 
     if (BuildConfig.DEBUG) Log.d(TAG, cmd.mkString(" "))
-    Console.runCommand(cmd.mkString(" "))
+    sstunnelPid = System.exec(cmd.mkString(" "))
   }
 
   def startDnsDaemon() {
@@ -361,10 +376,10 @@ class ShadowsocksVpnService extends VpnService with BaseService {
         val reject = ConfigUtils.getRejectList(getContext)
         val blackList = ConfigUtils.getBlackList(getContext)
         ConfigUtils.PDNSD_DIRECT.formatLocal(Locale.ENGLISH, "0.0.0.0", 8153,
-          Path.BASE + "pdnsd-vpn.pid", reject, blackList, 8163, ipv6)
+          reject, blackList, 8163, ipv6)
       } else {
         ConfigUtils.PDNSD_LOCAL.formatLocal(Locale.ENGLISH, "0.0.0.0", 8153,
-          Path.BASE + "pdnsd-vpn.pid", 8163, ipv6)
+          8163, ipv6)
       }
     }
     ConfigUtils.printToFile(new File(Path.BASE + "pdnsd-vpn.conf"))(p => {
@@ -373,7 +388,7 @@ class ShadowsocksVpnService extends VpnService with BaseService {
     val cmd = Path.BASE + "pdnsd -c " + Path.BASE + "pdnsd-vpn.conf"
 
     if (BuildConfig.DEBUG) Log.d(TAG, cmd)
-    Console.runCommand(cmd)
+    pdnsdPid = System.exec(cmd)
   }
 
   override def getContext = getBaseContext
@@ -446,8 +461,7 @@ class ShadowsocksVpnService extends VpnService with BaseService {
       + "--socks-server-addr 127.0.0.1:%d "
       + "--tunfd %d "
       + "--tunmtu %d "
-      + "--loglevel 3 "
-      + "--pid %stun2socks-vpn.pid")
+      + "--loglevel 3 ")
       .formatLocal(Locale.ENGLISH,
         PRIVATE_VLAN.formatLocal(Locale.ENGLISH, "2"),
         config.localPort, fd, VPN_MTU, Path.BASE)
@@ -462,7 +476,7 @@ class ShadowsocksVpnService extends VpnService with BaseService {
 
     if (BuildConfig.DEBUG) Log.d(TAG, cmd)
 
-    Console.runCommand(cmd)
+    tun2socksPid = System.exec(cmd)
 
     fd
   }
diff --git a/src/main/scala/com/github/shadowsocks/utils/ConfigUtils.scala b/src/main/scala/com/github/shadowsocks/utils/ConfigUtils.scala
index 73dc5db0..046eabba 100644
--- a/src/main/scala/com/github/shadowsocks/utils/ConfigUtils.scala
+++ b/src/main/scala/com/github/shadowsocks/utils/ConfigUtils.scala
@@ -51,16 +51,16 @@ object ConfigUtils {
     " log_debug = off;" +
     " log_info = off;" +
     " log = stderr;" +
-    " daemon = on;" +
+    " daemon = off;" +
     " redirector = iptables;" +
-    "}" +
+    " }\n" +
     "redsocks {" +
     " local_ip = 127.0.0.1;" +
     " local_port = 8123;" +
     " ip = 127.0.0.1;" +
     " port = %d;" +
     " type = socks5;" +
-    "}"
+    " }"
 
   val PDNSD_LOCAL =
     """
@@ -74,8 +74,7 @@ object ConfigUtils {
       | min_ttl = 15m;
       | max_ttl = 1w;
       | timeout = 10;
-      | daemon = on;
-      | pid_file = %s;
+      | daemon = off;
       |}
       |
       |server {
@@ -109,8 +108,7 @@ object ConfigUtils {
       | min_ttl = 15m;
       | max_ttl = 1w;
       | timeout = 10;
-      | daemon = on;
-      | pid_file = "%s";
+      | daemon = off;
       |}
       |
       |server {
@@ -153,8 +151,7 @@ object ConfigUtils {
       | min_ttl = 15m;
       | max_ttl = 1w;
       | timeout = 10;
-      | daemon = on;
-      | pid_file = "%s";
+      | daemon = off;
       |}
       |
       |server {