diff --git a/pykolab/imap/cyrus.py b/pykolab/imap/cyrus.py
--- a/pykolab/imap/cyrus.py
+++ b/pykolab/imap/cyrus.py
@@ -25,6 +25,7 @@
 
 import pykolab
 
+from pykolab.constants import *
 from pykolab.imap import IMAP
 from pykolab.translate import _
 
@@ -140,6 +141,10 @@
         """
         cyruslib.CYRUS.login(self, *args, **kw)
         self.separator = self.SEP
+        try:
+            self._id()
+        except Exception, errmsg:
+            pass
 
         log.debug(
                 _("Continuing with separator: %r") % (self.separator),
@@ -271,6 +276,13 @@
         from pykolab import imap_utf7
         return imap_utf7.decode(folder)
 
+    def _id(self, identity=None):
+        if identity is None:
+            identity = '("name" "Python/Kolab" "version" "%s")' % (__version__)
+
+        typ, dat = self.m._simple_command('ID', identity)
+        res, dat = self.m._untagged_response(typ, dat, 'ID')
+
     def _setquota(self, mailfolder, quota):
         """
             Login to the actual backend server.
@@ -372,11 +384,11 @@
         self.xfer(mailfolder, new_server)
 
     def undelete_mailfolder(
-            self,
-            mailfolder,
-            to_mailfolder=None,
-            recursive=True
-        ):
+                self,
+                mailfolder,
+                to_mailfolder=None,
+                recursive=True
+            ):
         """
             Login to the actual backend server, then "undelete" the mailfolder.
 
@@ -458,7 +470,7 @@
             target_server = self.find_mailfolder_server(target_folder)
 
             if hasattr(conf, 'dry_run') and not conf.dry_run:
-                if not target_server == self.server:
+                if target_server is not self.server:
                     self.xfer(undelete_folder, target_server)
 
                 self.rename(undelete_folder, target_folder)