diff --git a/extensions/amavis_quarantine/static/js/quarantine.js b/extensions/amavis_quarantine/static/js/quarantine.js
index 8e34dd589..5a6347947 100644
--- a/extensions/amavis_quarantine/static/js/quarantine.js
+++ b/extensions/amavis_quarantine/static/js/quarantine.js
@@ -30,7 +30,7 @@ function actioncallback(resp) {
 }
 
 function actionclick(evt) {
-  new Request.JSON({
+  new Request.JSON.mdb({
       url: evt.target.get("href"),
       onSuccess: actioncallback
   }).get();
diff --git a/extensions/sievefilters/static/js/lib.js b/extensions/sievefilters/static/js/lib.js
index d2c19da31..39add7588 100644
--- a/extensions/sievefilters/static/js/lib.js
+++ b/extensions/sievefilters/static/js/lib.js
@@ -14,7 +14,7 @@ function removefilter(evt) {
     if (!confirm(gettext("Remove this filter?"))) {
         return;
     }
-    new Request.JSON({
+    new Request.JSON.mdb({
         url: this.get("href"),
         onSuccess: function(response) {
             if (response.status == "ok") {
@@ -72,7 +72,7 @@ function loadfs(response) {
  * (remove, activate)
  */
 function send_command(cmd, extracb) {
-    new Request.JSON({
+    new Request.JSON.mdb({
         url: cmd,
         onSuccess: function(response) {
             if (response.status == "ko") {
@@ -116,7 +116,7 @@ function savefs(evt) {
     if (!check_prereqs(evt, gettext("Save changes?"))) {
         return;
     }
-    new Request.JSON({
+    new Request.JSON.mdb({
         url: $("feditor").get("action"),
         method: $("feditor").get("method"),
         data: $("feditor").toQueryString(),
@@ -177,7 +177,7 @@ function activatefs(evt) {
 
 function toggle_filter_state(event) {
     event.stop();
-    new Request.JSON({
+    new Request.JSON.mdb({
         url: this.get("href"),
         onSuccess: function(response) {
             if (response.status == "ok") {
@@ -193,7 +193,7 @@ function toggle_filter_state(event) {
 
 function move_filter(event) {
     event.stop();
-    new Request.JSON({
+    new Request.JSON.mdb({
         url: this.get("href"),
         onSuccess: function(response) {
             $("filters_list").set("html", response.content);
diff --git a/extensions/stats/templates/stats/index.html b/extensions/stats/templates/stats/index.html
index 6e33f0f4f..bd041abbd 100644
--- a/extensions/stats/templates/stats/index.html
+++ b/extensions/stats/templates/stats/index.html
@@ -68,8 +68,8 @@ window.addEvent("domready", function() {
     if (p == "") {
       return;
     }
-    new Request.JSON({url : url + "?" + p, noCache: true, 
-                      onSuccess : getgraph_callback}).get();
+    new Request.JSON.mdb({url : url + "?" + p, noCache: true, 
+                          onSuccess : getgraph_callback}).get();
   };
 
   {% if user.is_superuser %}
diff --git a/extensions/webmail/lib.py b/extensions/webmail/lib.py
index c823c075b..8d9281820 100644
--- a/extensions/webmail/lib.py
+++ b/extensions/webmail/lib.py
@@ -691,6 +691,9 @@ def html2plaintext(content):
     return plaintext
 
 def get_current_url(request):
+    if not request.session.has_key("folder"):
+        return ""
+
     res = "%s?page=%s" % (request.session["folder"], request.session["page"])
     for p in ["criteria", "pattern", "order"]:
         if p in request.session.keys():
diff --git a/extensions/webmail/static/js/fdmenu.js b/extensions/webmail/static/js/fdmenu.js
index 721d69ecd..570d6e80d 100644
--- a/extensions/webmail/static/js/fdmenu.js
+++ b/extensions/webmail/static/js/fdmenu.js
@@ -46,7 +46,7 @@ var FdMenu = new Class({
           if (!confirm(gettext("Delete folder?"))) {
             return;
           }
-          new Request.JSON({
+          new Request.JSON.mdb({
             url: evt.target.get("href"),
             method: "GET",
             onSuccess: function(resp) {
diff --git a/extensions/webmail/static/js/webmail.js b/extensions/webmail/static/js/webmail.js
index 74d6f283b..bdc67251c 100644
--- a/extensions/webmail/static/js/webmail.js
+++ b/extensions/webmail/static/js/webmail.js
@@ -219,13 +219,17 @@ function refreshFolder() {
     profile : "gray",
     spinner : true
   });
-  new Request.JSON({url: query, noCache : true, onSuccess: function(resp) {
-    var callback = ($defined(resp.callback)) ? resp.callback : "default";
+  new Request.JSON.mdb({
+      url: query,
+      noCache : true,
+      onSuccess: function(resp) {
+          var callback = ($defined(resp.callback)) ? resp.callback : "default";
 
-    current_anchor.get_callback(callback)(resp);
-    infobox.info(gettext("Done"));
-    infobox.hide(1);
-  }}).get();
+          current_anchor.get_callback(callback)(resp);
+          infobox.info(gettext("Done"));
+          infobox.hide(1);
+      }
+  }).get();
 }
 
 /*
@@ -240,7 +244,7 @@ function simple_request(url, params) {
     profile: "gray",
     spinner: true
   });
-  new Request.JSON({
+  new Request.JSON.mdb({
     url : url,
     onSuccess : function(response) {
       if (response.status == "ok") {
diff --git a/extensions/webmail/templates/webmail/attachments.html b/extensions/webmail/templates/webmail/attachments.html
index d1660e605..bf4f2e591 100644
--- a/extensions/webmail/templates/webmail/attachments.html
+++ b/extensions/webmail/templates/webmail/attachments.html
@@ -6,7 +6,7 @@
 <script type="text/javascript">
 function del_attachment(evt) {
     evt.stop();
-    new Request.JSON({
+    new Request.JSON.mdb({
         url: this.get("href"),
         onSuccess: function(resp) {
             this.getParent().dispose();
diff --git a/lib/middleware.py b/lib/middleware.py
index 61f11fc53..7f74557e0 100644
--- a/lib/middleware.py
+++ b/lib/middleware.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
 import re
-from django.http import Http404
+from django.http import Http404, HttpResponseRedirect
 from modoboa.admin.models import Extension
 
 class ExtControlMiddleware(object):
@@ -15,3 +15,10 @@ class ExtControlMiddleware(object):
         if ext.enabled:
             return None
         raise Http404
+
+class AjaxLoginRedirect(object):
+    def process_response(self, request, response):
+        if request.is_ajax():
+            if type(response) == HttpResponseRedirect:
+                response.status_code = 278
+        return response
diff --git a/settings_sample.py b/settings_sample.py
index ef83a20ce..211cfaa2a 100644
--- a/settings_sample.py
+++ b/settings_sample.py
@@ -88,6 +88,7 @@ MIDDLEWARE_CLASSES = (
     'django.contrib.auth.middleware.AuthenticationMiddleware',
     'django.contrib.messages.middleware.MessageMiddleware',
     'django.middleware.locale.LocaleMiddleware',
+    'modoboa.lib.middleware.AjaxLoginRedirect',
     'modoboa.lib.middleware.ExtControlMiddleware',
     'modoboa.extensions.webmail.middleware.WebmailErrorMiddleware',
 )
diff --git a/static/js/anchor_nav.js b/static/js/anchor_nav.js
index 055896f50..40aab8b9d 100644
--- a/static/js/anchor_nav.js
+++ b/static/js/anchor_nav.js
@@ -206,6 +206,9 @@ var AnchorNavigation = new Class({
         new Request.JSON({
             url: query,
             noCache : true,
+            onComplete: function() {
+                ajax_login_redirect();
+            },
             onSuccess: function(resp) {
                 var callback = ($defined(resp.callback)) ? resp.callback : "default";
                 this.callbacks[callback](resp);
diff --git a/static/js/common.js b/static/js/common.js
index 77c5ba472..78218ef30 100644
--- a/static/js/common.js
+++ b/static/js/common.js
@@ -229,4 +229,4 @@ saveparams = function(id, message) {
             }
         }).send();
     });
-};
\ No newline at end of file
+};
diff --git a/static/js/utils.js b/static/js/utils.js
new file mode 100644
index 000000000..51787fb61
--- /dev/null
+++ b/static/js/utils.js
@@ -0,0 +1,30 @@
+/*
+ * Collection of functions that are accessible to every page.
+ */
+
+/*
+ * Simple function that redirect ajax requests to the login page if
+ * the status code received with a response is equal to 278.
+ */
+function ajax_login_redirect() {
+    if (this.status != 278) {
+        return;
+    }
+    var params = "?next=" + window.location.pathname;
+
+    window.location.href =
+        this.xhr.getResponseHeader("Location").replace(/\?.*$/, params);
+}
+
+/*
+ * Simple wrapper around Request.JSON. We just ensure that
+ * redirections are correctly catched. (on session timeout for
+ * example)
+ */
+Request.JSON.mdb = new Class({
+    Extends: Request.JSON,
+
+    options: {
+        onComplete: ajax_login_redirect
+    }
+});
\ No newline at end of file
diff --git a/templates/admin/add_domain_admin.html b/templates/admin/add_domain_admin.html
index 17ab5d126..3d1bad5da 100644
--- a/templates/admin/add_domain_admin.html
+++ b/templates/admin/add_domain_admin.html
@@ -13,7 +13,9 @@ domadminform_init = function() {
 	{% url domains as doms_url %}
 	new Request({
 	    url: "{% url domains %}" + domid + "/rawmboxes/?target=permissions",
-	    method: "get", onSuccess: function(data) {
+	    method: "get", 
+            onComplete: ajax_login_redirect,
+            onSuccess: function(data) {
 		$("id_user").set("html", data);
 		$("id_user").options[0].setProperty("selected", "selected");
 	    }
diff --git a/templates/admin/mbaliasform.html b/templates/admin/mbaliasform.html
index 3f7e5e8ec..db689996e 100644
--- a/templates/admin/mbaliasform.html
+++ b/templates/admin/mbaliasform.html
@@ -16,7 +16,8 @@ function init_form() {
     new Autocompleter.Request.JSON("id_targets", 
                                    "{% url admin.views.mailboxes_search %}", {
         postVar: "search",
-        minLength: 3
+        minLength: 3,
+        onComplete: ajax_login_redirect
     });
 }
 
diff --git a/templates/layout_simple.html b/templates/layout_simple.html
index 69159e8e4..bdea1407a 100644
--- a/templates/layout_simple.html
+++ b/templates/layout_simple.html
@@ -9,6 +9,7 @@
   <script src="{{ MEDIA_URL }}js/mootools.js" type="text/javascript"></script>
   <script src="{{ MEDIA_URL }}js/mootools-more.js" type="text/javascript"></script>
   <script src="{{ MEDIA_URL }}js/SqueezeBox.js" type="text/javascript"></script>
+  <script src="{{ MEDIA_URL }}js/utils.js" type="text/javascript"></script>
   {% url django.views.i18n.javascript_catalog as catalog_url %}
   <script type="text/javascript" src="{{ catalog_url }}"></script>
   {% block html_head %}{% endblock %}
diff --git a/templates/nlayout.html b/templates/nlayout.html
index 3e34463f8..fe931702a 100644
--- a/templates/nlayout.html
+++ b/templates/nlayout.html
@@ -14,6 +14,7 @@
   <script src="{{ MEDIA_URL }}js/SqueezeBox.js" type="text/javascript"></script>
   <script src="{{ MEDIA_URL }}js/infobox.js" type="text/javascript"></script>
   <script src="{{ MEDIA_URL }}js/common.js" type="text/javascript"></script>
+  <script src="{{ MEDIA_URL }}js/utils.js" type="text/javascript"></script>
   {% url django.views.i18n.javascript_catalog as catalog_url %}
   <script type="text/javascript" src="{{ catalog_url }}"></script>
   <script type="text/javascript">