diff --git a/OffloadingDemo/mobile/src/main/java/edu/ucsb/cs/sandlab/offloadingdemo/MainActivity.java b/OffloadingDemo/mobile/src/main/java/edu/ucsb/cs/sandlab/offloadingdemo/MainActivity.java
index b76a9d0..510de80 100755
--- a/OffloadingDemo/mobile/src/main/java/edu/ucsb/cs/sandlab/offloadingdemo/MainActivity.java
+++ b/OffloadingDemo/mobile/src/main/java/edu/ucsb/cs/sandlab/offloadingdemo/MainActivity.java
@@ -14,6 +14,7 @@ import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
 import android.widget.Button;
+import android.widget.EditText;
 import android.widget.TextView;
 import android.widget.Toast;
 
@@ -196,10 +197,34 @@ class MainActivity extends Activity {
      * @param myflag:
      */
     protected void startRecording(boolean myflag) {
+        AlertDialog.Builder adb;
         final boolean flagRecv = myflag;
         final ArrayList<Integer> selectedItems = new ArrayList<>();
 
-        AlertDialog.Builder adb = new AlertDialog.Builder(MainActivity.this);
+        // first initialize the target ip and mac
+        EditText edit_remote_ip = (EditText) findViewById(R.id.remote_ip);
+        EditText edit_remote_mac = (EditText) findViewById(R.id.remote_mac);
+        String string_remote_ip = edit_remote_ip.getText().toString();
+        String string_remote_mac = edit_remote_mac.getText().toString();
+        // check if ip is in valid format and reachable
+        if (Utilities.validIP(string_remote_ip)) {
+            remoteIP = string_remote_ip;
+        } else {
+            Toast.makeText(this, "Entered IP is not right, will use " + remoteIP + "instead",
+                    Toast.LENGTH_SHORT);
+        }
+        // check if mac is in valid format
+        if (Utilities.validMAC(string_remote_mac)) {
+            remoteMAC = string_remote_mac;
+        } else {
+            Toast.makeText(this, "Entered MAC is not right, will use " + remoteMAC + "instead",
+                    Toast.LENGTH_SHORT);
+        }
+        Log.d(TAG, "remote IP is set to " + remoteIP);
+        Log.d(TAG, "remote MAC is set to " + remoteMAC);
+
+        // then create a dialog for options
+        adb = new AlertDialog.Builder(MainActivity.this);
         adb.setMultiChoiceItems(Utilities.existedItems, null,
                 new DialogInterface.OnMultiChoiceClickListener() {
             @Override
@@ -895,8 +920,8 @@ class MainActivity extends Activity {
                                             "time_wait_for is set to " + time_wait_for + "ms\n");
                                 }
                             });
-                            Log.d(TAG, "time_wait_for is set to " + time_wait_for + "ms");
                         }
+                        Log.d(TAG, "time_wait_for is set to " + time_wait_for + "ms");
                     }
                 });
                 mDialog.create().show();
diff --git a/OffloadingDemo/mobile/src/main/java/edu/ucsb/cs/sandlab/offloadingdemo/Utilities.java b/OffloadingDemo/mobile/src/main/java/edu/ucsb/cs/sandlab/offloadingdemo/Utilities.java
index 9d5948e..bcab4f5 100755
--- a/OffloadingDemo/mobile/src/main/java/edu/ucsb/cs/sandlab/offloadingdemo/Utilities.java
+++ b/OffloadingDemo/mobile/src/main/java/edu/ucsb/cs/sandlab/offloadingdemo/Utilities.java
@@ -22,6 +22,8 @@ import java.util.ArrayList;
 import java.util.Date;
 import java.util.Enumeration;
 import java.util.Locale;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * Created by yanzi on 10/1/15.
@@ -552,4 +554,46 @@ class Utilities {
             }
         });
     }
+
+    /**
+     * check if is a valid IP (pingable)
+     * @param ip: ip address as string
+     * @return boolean
+     */
+    static boolean validIP(String ip) {
+        // only check the ip ad ipv4
+        if ( ip == null || ip.isEmpty() ) return false;
+        int i;
+        String[] parts;
+        try {
+            parts = ip.split( "\\." );
+        } catch (Exception ignored) {
+            return false;
+        }
+        if ( parts.length != 4 ) return false;
+        for ( String s : parts ) {
+            i = Integer.parseInt(s);
+            if ((i < 0) || (i > 255)) return false;
+        }
+        if (ip.endsWith(".")) return false;
+        // ping the ip and see if it is reachable
+        try {
+            return InetAddress.getByName(ip).isReachable(5);
+        } catch (IOException ignored) {
+            return false;
+        }
+    }
+
+    /**
+     * check if is a valid MAC
+     * @param mac: mac address as string
+     * @return boolean
+     */
+    static boolean validMAC(String mac) {
+        // use regular expression to validate a mac address
+        // the only valid format is xx:xx:xx:xx:xx:xx
+        Pattern p = Pattern.compile("^([a-fA-F0-9][:]){5}[a-fA-F0-9][:]$");
+        Matcher m = p.matcher(mac);
+        return m.find();
+    }
 }
diff --git a/OffloadingDemo/mobile/src/main/res/layout/activity_main.xml b/OffloadingDemo/mobile/src/main/res/layout/activity_main.xml
index 21c83df..34e11c9 100755
--- a/OffloadingDemo/mobile/src/main/res/layout/activity_main.xml
+++ b/OffloadingDemo/mobile/src/main/res/layout/activity_main.xml
@@ -40,6 +40,50 @@
 
         </LinearLayout>
 
+        <LinearLayout
+            android:id="@+id/container_target_ipmac"
+            android:layout_width="match_parent"
+            android:layout_height="0dp"
+            android:orientation="horizontal"
+            android:layout_weight="0.4">
+
+            <TextView
+                android:layout_width="0dp"
+                android:layout_height="match_parent"
+                android:layout_weight="1"
+                android:text="IP:"
+                android:gravity="center"
+                android:textSize="16dp"/>
+
+            <EditText
+                android:id="@+id/remote_ip"
+                android:layout_width="0dp"
+                android:layout_height="match_parent"
+                android:layout_weight="3"
+                android:hint="Remote IP"
+                android:text="192.168.10.1"
+                android:inputType="text"
+                android:textSize="16dp"/>
+
+            <TextView
+                android:layout_width="0dp"
+                android:layout_height="match_parent"
+                android:layout_weight="1"
+                android:text="MAC:"
+                android:gravity="center"
+                android:textSize="16dp"/>
+
+            <EditText
+                android:id="@+id/remote_mac"
+                android:layout_width="0dp"
+                android:layout_height="match_parent"
+                android:layout_weight="3"
+                android:hint="Remote MAC"
+                android:text="f0:de:f1:0b:45:4a"
+                android:inputType="text"
+                android:textSize="16dp"/>
+
+        </LinearLayout>
         <!--<HorizontalScrollView-->
             <!--android:id="@+id/container_config"-->
             <!--android:layout_width="match_parent"-->