I have a WordPress installation which uses LDAP against Active Directory to authenticate users. I upgraded PHP to version 5.3.8 from version 5.1.6 (using the Atomic Repository) and also upgraded WordPress and the LDAP plugin. I’m not sure which upgrade caused me problems but users were then unable to login with their LDAP accounts. The error in the log was:
[Mon Sep 05 15:32:06 2011] [error] [client 123.111.222.555] PHP Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘ldapShowOptionsCss’ not found or invalid function name in /var/www/wp-includes/plugin.php on line 405, referer: http://domainname.com/wp-admin/network/settings.php
[Mon Sep 05 15:33:37 2011] [error] [client 123.111.222.555] PHP Warning: ldap_start_tls() [<a href=’function.ldap-start-tls’>function.ldap-start-tls</a>]: Unable to start TLS: Can’t contact LDAP server in /var/www/wp-content/mu-plugins/ldap/lib/ldap_core.php on line 63
So I checked my LDAP settings and I had already had:
TLS_REQCERT never
in /etc/ldap.conf and /etc/openldap/ldap.conf
So I switched the LDAP settings in the WordPress LDAP plugin from using TLS to SSL and the LDAP logins work again.
