I struggled for a while to get WordPress to use Active Directory credentials on CentOS 7. Below is how I finally got it to work.

First, install necessary packages:

sudo yum -y install openldap-clients php-ldap

If you use self-signed certificate for ldaps, you’ll need to modify /etc/openldap/ldap.conf

HOST <HOSTNAME_OF_LDAP_SERVER>
PORT 636
TLS_CACERT <PATH_TO_CA_CERT>
TLS_REQCERT demand

With the above settings you can test your ldap string with ldapsearch

ldapsearch -x -D "<BIND USERNAME>" -b "<BASE_DN>" -H ldaps://<LDAP_SERVER_HOSTNAME> -W sAMAccountName=<USER_TO_QUERY>

Once ldapsearch works properly, install your AD integration plugin.  I use AuthLDAP by Andreas Heigl

I struggled with which LDAP strings and filters to use. This is what finally got everything working with our Active Directory environment:

LDAP URI: ldaps://<BIND_USERNAME>:<BIND_PASSWORD>@<AD_SERVER_ADDRESS>:636/<BASE DN>

Filter: (sAMAccountName=%s)

Name-Attribute: givenName

User-ID Attribute: sAMAccountName

Second Name Attribute: sn

Group-Attribute:memberOf

Group-Separator:  _

Group-Filter: (&(objectClass=user)(sAMAccountName=%s)(memberOf=*))

Role – group mapping

I had to change Group-Separator to _ above, because in Role – group mapping for active directory, you must put the FQDN, which includes commas. Put an underscore separated list of FQDNS for each of these fields you want.