Index: b/dirmngr/dirmngr_ldap.c
===================================================================
--- b/dirmngr/dirmngr_ldap.c
+++ b/dirmngr/dirmngr_ldap.c
@@ -641,6 +641,18 @@
   /* Fixme:  Can we use MYOPT->user or is it shared with other theeads?.  */
   ret = my_ldap_simple_bind_s (ld, myopt->user, myopt->pass);
   npth_protect ();
+#ifdef LDAP_VERSION3
+  if (ret == LDAP_PROTOCOL_ERROR)
+    {
+      int version = LDAP_VERSION3;
+      /* Protocol error could mean that the server only supports v3 */
+      npth_unprotect ();
+      log_debug ("Protocol error, retrying bind with V3 Protocol. \n");
+      ldap_set_option (ld, LDAP_OPT_PROTOCOL_VERSION, &version);
+      ret = my_ldap_simple_bind_s (ld, myopt->user, myopt->pass);
+      npth_protect ();
+    }
+#endif
   if (ret)
     {
       log_error (_("binding to '%s:%d' failed: %s\n"),