Had to post this as I recently encountered an annoyance again today with LDAP on Redhat timing out if the LDAP servers can’t be reached. Sometimes, when a Linux box boots and hangs on some services like postfix, systembus, system logger, anything with a special user/group that will be mistakenly authenticated against LDAP. Not a problem if the network is there, but if not it will time out.
Add this to /etc/ldap.conf
You could also fine tune with the following.