diff --git a/openvimd b/openvimd
index f2dbd53..b50187d 100755
--- a/openvimd
+++ b/openvimd
@@ -231,10 +231,22 @@
             logger.error(error_msg)
             exit(1)
 
+        if config_dic['network_type'] == 'ovs' \
+                and config_dic['ovs_controller_ip'] == 'localhost' \
+                and not (config_dic['mode'] == 'test' or config_dic['mode'] == "OF only"):
+
+            error_msg = "Error: invalid value '{}' for ovs_controller_ip at {}. " \
+                        "Use a valid IP address".format(config_dic['ovs_controller_ip'], config_file)
+
+            print ("!! {} ".format(error_msg))
+            logger.error(error_msg)
+            exit(1)
+
         if config_dic['mode'] != 'normal':
             print ('!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!')
             print ("!! Warning, openvimd in TEST mode '{}'".format(config_dic['mode']))
             print ('!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!')
+
         config_dic['version'] = ovim.ovim.get_version()
         config_dic["logger_name"] = "openvim"
 
diff --git a/osm_openvim/host_thread.py b/osm_openvim/host_thread.py
index 00d253e..b8f051c 100644
--- a/osm_openvim/host_thread.py
+++ b/osm_openvim/host_thread.py
@@ -101,6 +101,7 @@
         self.queueLock = threading.Lock()
         self.taskQueue = Queue.Queue(2000)
         self.ssh_conn = None
+        self.connectivity = True
         self.lvirt_conn_uri = "qemu+ssh://{user}@{host}/system?no_tty=1&no_verify=1".format(
             user=self.user, host=self.host)
         if keyfile:
@@ -118,6 +119,28 @@
             text = e.args[0]
             self.logger.error("ssh_connect ssh Exception: " + text)
 
+    def check_connectivity(self):
+        if not self.test:
+
+            try:
+                if not self.ssh_conn:
+                    self.ssh_connect()
+
+                command = 'sudo brctl show'
+                (_, stdout, stderr) = self.ssh_conn.exec_command(command, timeout=10)
+                content = stderr.read()
+                if len(content) > 0:
+                    self.connectivity = False
+                    self.logger.error("ssh conection error")
+            except paramiko.ssh_exception.SSHException as e:
+                text = e.args[0]
+                self.connectivity = False
+                self.logger.error("ssh_connect ssh Exception: " + text)
+                raise paramiko.ssh_exception.SSHException("ssh error conection")
+            except Exception as e:
+                self.connectivity = False
+                raise paramiko.ssh_exception.SSHException("ssh error conection")
+
     def load_localinfo(self):
         if not self.test:
             try:
@@ -732,8 +755,10 @@
         Create a bridge in compute OVS to allocate VMs
         :return: True if success
         """
-        if self.test:
+        if self.test or not self.connectivity:
             return True
+
+
         try:
             command = 'sudo ovs-vsctl --may-exist add-br br-int -- set Bridge br-int stp_enable=true'
             self.logger.debug("command: " + command)
@@ -757,7 +782,7 @@
         :return:
         """
 
-        if self.test:
+        if self.test or not self.connectivity:
             return True
         try:
             port_name = 'ovim-' + str(vlan)
@@ -783,7 +808,7 @@
         :param dhcp_path: conf fiel path that live in namespace side
         :return:
         """
-        if self.test:
+        if self.test or not self.connectivity:
             return True
         if not self.is_dhcp_port_free(vlan, net_uuid):
             return True
@@ -1253,7 +1278,7 @@
         :param remote_ip: tunnel endpoint remote compute ip.
         :return:
         """
-        if self.test:
+        if self.test or not self.connectivity:
             return True
         try:
             command = 'sudo ovs-vsctl add-port br-int ' + vxlan_interface + \
@@ -1279,7 +1304,7 @@
         :param vxlan_interface: vlxan name to be delete it.
         :return: True if success.
         """
-        if self.test:
+        if self.test or not self.connectivity:
             return True
         try:
             command = 'sudo ovs-vsctl del-port br-int ' + vxlan_interface
@@ -1302,7 +1327,7 @@
         Delete a OVS bridge from  a compute.
         :return: True if success
         """
-        if self.test:
+        if self.test or not self.connectivity:
             return True
         try:
             command = 'sudo ovs-vsctl del-br br-int'
diff --git a/osm_openvim/httpserver.py b/osm_openvim/httpserver.py
index aa23d89..7126e21 100644
--- a/osm_openvim/httpserver.py
+++ b/osm_openvim/httpserver.py
@@ -640,8 +640,9 @@
                                     test=host_test_mode, image_path=config_dic['host_image_path'],
                                     version=config_dic['version'], host_id=content['uuid'],
                                     develop_mode=host_develop_mode, develop_bridge_iface=host_develop_bridge_iface)
+
             thread.start()
-            config_dic['host_threads'][ content['uuid'] ] = thread
+            config_dic['host_threads'][content['uuid']] = thread
 
             if config_dic['network_type'] == 'ovs':
                 # create bridge
@@ -650,7 +651,7 @@
                 # check if more host exist
                 create_vxlan_mesh(content['uuid'])
 
-        #return host data
+        # return host data
         change_keys_http2db(content, http2db_host, reverse=True)
         if len(warning_text)>0:
             content["warning"]= warning_text
diff --git a/osm_openvim/ovim.py b/osm_openvim/ovim.py
index 82d06ce..dc21e2d 100755
--- a/osm_openvim/ovim.py
+++ b/osm_openvim/ovim.py
@@ -191,6 +191,40 @@
         self.config["db_lock"] = threading.Lock()
 
         self.of_test_mode = False if self.config['mode'] == 'normal' or self.config['mode'] == "OF only" else True
+
+        # Create one thread for each host
+        host_test_mode = True if self.config['mode'] == 'test' or self.config['mode'] == "OF only" else False
+        host_develop_mode = True if self.config['mode'] == 'development' else False
+        host_develop_bridge_iface = self.config.get('development_bridge', None)
+
+        # get host list from data base before starting threads
+        r, hosts = self.db.get_table(SELECT=('name', 'ip_name', 'user', 'uuid', 'password', 'keyfile'),
+                                     FROM='hosts', WHERE={'status': 'ok'})
+        if r < 0:
+            raise ovimException("Cannot get hosts from database {}".format(hosts))
+
+        self.config['host_threads'] = {}
+
+        for host in hosts:
+            thread = ht.host_thread(name=host['name'], user=host['user'], host=host['ip_name'], db=self.config["db"],
+                                    password=host['password'],
+                                    keyfile=host.get('keyfile', self.config["host_ssh_keyfile"]),
+                                    db_lock=self.config["db_lock"], test=host_test_mode,
+                                    image_path=self.config['host_image_path'],
+                                    version=self.config['version'], host_id=host['uuid'],
+                                    develop_mode=host_develop_mode,
+                                    develop_bridge_iface=host_develop_bridge_iface,
+                                    logger_name=self.logger_name + ".host." + host['name'],
+                                    debug=self.config.get('log_level_host'))
+
+            try:
+                thread.check_connectivity()
+            except Exception as e:
+                self.logger.critical('Error detected for compute = {} with ip = {}'
+                                     .format(host['name'], host['ip_name']))
+
+            self.config['host_threads'][host['uuid']] = thread
+
         # precreate interfaces; [bridge:<host_bridge_name>, VLAN used at Host, uuid of network camping in this bridge,
         # speed in Gbit/s
 
@@ -238,31 +272,7 @@
             thread.start()
             self.config['dhcp_thread'] = thread
 
-        # Create one thread for each host
-        host_test_mode = True if self.config['mode'] == 'test' or self.config['mode'] == "OF only" else False
-        host_develop_mode = True if self.config['mode'] == 'development' else False
-        host_develop_bridge_iface = self.config.get('development_bridge', None)
 
-        # get host list from data base before starting threads
-        r, hosts = self.db.get_table(SELECT=('name', 'ip_name', 'user', 'uuid', 'password', 'keyfile'),
-                                     FROM='hosts', WHERE={'status': 'ok'})
-        if r < 0:
-            raise ovimException("Cannot get hosts from database {}".format(hosts))
-
-        self.config['host_threads'] = {}
-        for host in hosts:
-            thread = ht.host_thread(name=host['name'], user=host['user'], host=host['ip_name'], db=self.config["db"],
-                                    password=host['password'],
-                                    keyfile=host.get('keyfile', self.config["host_ssh_keyfile"]),
-                                    db_lock=self.config["db_lock"], test=host_test_mode,
-                                    image_path=self.config['host_image_path'],
-                                    version=self.config['version'], host_id=host['uuid'],
-                                    develop_mode=host_develop_mode,
-                                    develop_bridge_iface=host_develop_bridge_iface,
-                                    logger_name=self.logger_name + ".host." + host['name'],
-                                    debug=self.config.get('log_level_host'))
-            thread.start()
-            self.config['host_threads'][host['uuid']] = thread
 
         # create ovs dhcp thread
         result, content = self.db.get_table(FROM='nets')
@@ -1375,8 +1385,11 @@
                                    debug=self.config.get('log_level_host'))
         # dhcp_host.start()
         self.config['host_threads']['openvim_controller'] = dhcp_host
-        if not host_test_mode:
-            dhcp_host.ssh_connect()
+        try:
+            dhcp_host.check_connectivity()
+        except Exception as e:
+           pass
+
         return dhcp_host
 
     def launch_dhcp_server(self, vlan, first_ip, last_ip, cidr, gateway):