title: ldap server unreachable cause plone/zope server down
body: <p>I have a plone installation (4.2.5) with <strong>plone.app.ldap</strong> add-on. There is a site with plone-ldap enabled and our ldap server was changed to another domain/IP. So on, zope server downs on plone-ldap retrieving ldap information. Nothing more works even root ZMI.</p>
  
  <p>Any request to server doesn't load anything few seconds after plone restart. Therefore I can't reconfigure our new ldap server neither by our site or ZMI interface.</p>
  
  <p>In such case, How can I proceed to reconfigure the new ldap server on plone-ldap component? Is there some script application similar to ZMI to do this? Is it a known bug?</p>
  
  <p>Some logs:</p>
  
  <p>1) Zeoserver.log</p>
  
  <pre><code>2016-06-06T15:52:04 new connection ('127.0.0.1', 40051): &lt;ManagedServerConnection ('127.0.0.1', 40051)&gt;
  2016-06-06T15:52:04 (127.0.0.1:40049) received handshake 'Z3101'
  2016-06-06T15:52:04 (unconnected) disconnected
  2016-06-06T15:52:04 (unconnected) disconnected
  2016-06-06T15:52:08 new connection ('127.0.0.1', 40052): &lt;ManagedServerConnection ('127.0.0.1', 40052)&gt;
  2016-06-06T15:52:08 new connection ('127.0.0.1', 40053): &lt;ManagedServerConnection ('127.0.0.1', 40053)&gt;
  2016-06-06T15:52:08 new connection ('127.0.0.1', 40054): **&lt;ManagedServerConnection ('127.0.0.1', 40054)&gt;
  2016-06-06T15:52:08 (127.0.0.1:40052) received handshake 'Z3101'
  2016-06-06T15:52:08 (unconnected) disconnected
  2016-06-06T15:52:08 (unconnected) disconnected**
  </code></pre>
  
  <p>2) client1/event.log</p>
  
  <pre><code>2016-06-06T15:53:12 ERROR event.LDAPDelegate {'desc': "Can't contact LDAP server"}
  Traceback (most recent call last):
    File "/usr/local/Plone/buildout-cache/eggs/Products.LDAPUserFolder-2.26-py2.7.egg/Products/LDAPUserFolder/LDAPDelegate.py", line 366, in search
      connection = self.connect(bind_dn=bind_dn, bind_pwd=bind_pwd)
    File "/usr/local/Plone/buildout-cache/eggs/Products.LDAPUserFolder-2.26-py2.7.egg/Products/LDAPUserFolder/LDAPDelegate.py", line 265, in connect
      raise e
  **SERVER_DOWN: {'desc': "Can't contact LDAP server"}**
  </code></pre>