On two machines that were able to authenticate users against our OpenLDAP server... someone configured another Ethernet interface to use DHCP. LDAP hasn't worked since. /etc/ldap.conf hasn't changed. These machines can ping the LDAP server (on same subnet) and can see other services, like ntpd But attempts to log in as an LDAP user result in

ldap_simple_bind: Can't contact LDAP server

in /var/log/messages.

I'm stumped.