LDAP_SUCCES on ldap_search_ext when host is unreachable

Hello,

I work on switch over ldap server and i have a problem when the host is unreachable. For information, I use old versions (ldap sdk 5.1.5) but i have the same problem with ldap sdk 6.0.7.

My test is simple, i create a rules IPTABLES to drop packets to first ldap server and i request the server with ldap_search_ext. This function return LDAP_SUCCESS while the server is unreachable.
On an other test, i stop ldap service and ldap_search_ext return 81 or ldap_can't contact ldap serveur.

So, my server don't execute second search on the second server.

For information, my programme test connection on start and create handle on first server who's connect. every 3000 ms, i bind my two server to verify if is always up.

Thanks,
Clement