diff --git a/sat/core/sat_main.py b/sat/core/sat_main.py
index 64d0024d..ded0cc73 100644
--- a/sat/core/sat_main.py
+++ b/sat/core/sat_main.py
@@ -418,7 +418,7 @@ class SAT(service.Service):
 
         def connectProfile(__=None):
             if self.isConnected(profile):
-                log.info(_("already connected !"))
+                log.info(_(u"already connected !"))
                 return True
 
             if self.memory.isComponent(profile):
diff --git a/sat/core/xmpp.py b/sat/core/xmpp.py
index 1df1b043..34a0319a 100644
--- a/sat/core/xmpp.py
+++ b/sat/core/xmpp.py
@@ -320,6 +320,43 @@ class SatXMPPEntity(object):
             return
         return cb(connector, reason)
 
+    def networkDisabled(self):
+        """Indicate that network has been completely disabled
+
+        In other words, internet is not available anymore and transport must be stopped.
+        Retrying is disabled too, as it makes no sense to try without network, and it may
+        use resources (notably battery on mobiles).
+        """
+        log.info(_(u"stopping connection because of network disabled"))
+        self.factory.continueTrying = 0
+        self._network_disabled = True
+        if self.xmlstream is not None:
+            self.xmlstream.transport.abortConnection()
+
+    def networkEnabled(self):
+        """Indicate that network has been (re)enabled
+
+        This happens when e.g. user activate WIFI connection.
+        """
+        try:
+            connector = self._saved_connector
+            network_disabled = self._network_disabled
+        except AttributeError:
+            # connection has not been stopped by networkDisabled
+            # we don't have to restart it
+            log.debug(u"no connection to restart")
+            return
+        else:
+            del self._network_disabled
+            if not network_disabled:
+                raise exceptions.InternalError(u"network_disabled should be True")
+        log.info(_(u"network is available, trying to connect"))
+        # we want to be sure to start fresh
+        self.factory.resetDelay()
+        # we have a saved connector, meaning the connection has been stopped previously
+        # we can now try to reconnect
+        connector.connect()
+
     def _connected(self, xs):
         send_hooks = []
         receive_hooks = []
@@ -359,6 +396,13 @@ class SatXMPPEntity(object):
                               u"somebody is trying to spy on you.\n"
                               u"Please contact your server administrator."))
                         self.factory.stopTrying()
+                        try:
+                            # with invalid certificate, we should not retry to connect
+                            # so we delete saved connector to avoid reconnection if
+                            # networkEnabled is called.
+                            del self._saved_connector
+                        except AttributeError:
+                            pass
                 except (IndexError, TypeError):
                     pass
             self.conn_deferred.errback(err)