Hello OpenLDAPs, Any LDAP search request with '-H ldap://<IP_LDAP_server>/' option returns 'Can't contact LDAP server (-1)' (see below). When the '-H ...' option is left out or when '-H ldap:///' is used, the expected result is returned (see below). The 'ldapsearch -x -H ldap://<IP_LDAP_server>/ ...' behaves the same from the server as from a client on the same LAN. Thanks for helping me to get rid of this problem. Thierry # ldapsearch -x -H ldap://192.168.100.11 -D "uid=thierry,ou=People,ou=linux,dc=be" -w password -b ou=linux,dc=be -LLL memberUid -v ldap_initialize( ldap://192.168.100.11:389/??base ) ldap_result: Can't contact LDAP server (-1) # ldapsearch -x -D "uid=thierry,ou=People,ou=linux,dc=be" -w password -b ou=linux,dc=be -LLL memberUid -v ldap_initialize( <DEFAULT> ) filter: (objectclass=*) requesting: memberUid dn: cn=thierry,ou=Group,ou=linux,dc=be memberUid: thierry # ldapsearch -x -H ldap:/// -D "uid=thierry,ou=People,ou=linux,dc=be" -w password -b ou=linux,dc=be -LLL memberUid -v ldap_initialize( ldap://:389/??base ) filter: (objectclass=*) requesting: memberUid memberUid: thierry