Update Method doesn't see value set by other thread

I'm trying to move an object when a socket client receive a "move" message. Message is being received and everything but i have a problem. I'm setting the bool isMoving to true on the socket callback but the update method almost always sees it as false. I know the bool is being set because is logging right before it but the log "Moving" that i have inside the update method almost never runs, one or two times it ran and the object moved (when i sent like a 100 messages), i don't know why sometimes it works. I'm just testing before i start making a multiplayer server, i tried to use locks and making the variable Volatile but it doesn't work. Is my bool probably being reset? Is there a better way of doing this? I cannot find a good sample of a MonoBehaviour controlled by a Socket

 using UnityEngine;
 using System.Collections;
 using System;
 using System.Net;
 using System.Net.Sockets;
 
 public class BallController : MonoBehaviour {
 
     private Socket _clientSocket = new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);
     private byte[] _recieveBuffer = new byte[8142];
     
     public volatile Boolean isMoving;
     
     private Rigidbody body;
     private object _locker = new object ();
 
     // Use this for initialization
     void Start () {
         body = GetComponent<Rigidbody>();
         SetupServer();
     }
 
     // Update is called once per frame
     void Update () {
         lock (_locker) {
             if (isMoving) {
 
                 Debug.Log ("Moving");
                 body.AddForce (new Vector3 (0.1435345f * .2f, 0, 0), ForceMode.Impulse);
 
                 isMoving = false;
 
             }
         }
 
         }
 
     private void SetupServer()
     {
         try
         {
             _clientSocket.Connect(new IPEndPoint(IPAddress.Loopback,6670));
         }
         catch(SocketException ex)
         {
             Debug.Log(ex.Message);
         }
 
         startReceiving();
     }
 
     private void startReceiving() {
         _clientSocket.BeginReceive(_recieveBuffer,0,_recieveBuffer.Length,SocketFlags.None,new AsyncCallback(ReceiveCallback),null);
     }
 
     private void ReceiveCallback(IAsyncResult AR)
     {
         //Check how much bytes are recieved and call EndRecieve to finalize handshake
         int recieved = _clientSocket.EndReceive(AR);
 
         if(recieved <= 0)
             return;
 
         //Copy the recieved data into new buffer , to avoid null bytes
         byte[] recData = new byte[recieved];
 
         Buffer.BlockCopy(_recieveBuffer,0,recData,0,recieved);
         
         // Convert bytes to String
         string result = System.Text.Encoding.UTF8.GetString(recData).Trim();
 
         if (!String.IsNullOrEmpty (result) && result.Equals ("move")) {
 
             Debug.Log ("Received Move");
 
             lock (_locker) {
                 isMoving = true;
             }
 
         }
 
         //Start receiving again
         startReceiving();
     }
 }