Mention how to customize OpenLDAP configuration.

en_US/iredmail-easy/2-iredmail-easy.best.practice.md

@@ -188,6 +188,45 @@ ALL | `first_domain_admin_password` | Password of the mail user `postmaster@<you
 max_connections     = 1024
 ```
 
+### OpenLDAP
+
+- `/opt/iredmail/custom/openldap/schema/`
+
+    Extra LDAP schema files must be stored in this directory, owned by OpenLDAP
+    daemon user and group with permission 0640.
+
+- `/opt/iredmail/custom/openldap/conf.d/global.conf`
+
+    Extra global settings should be stored in this file. For example, you can
+    load extra LDAP schema file by adding line below:
+
+    ```
+    include /opt/iredmail/custom/openldap/schema/custom.schema
+    ```
+
+- `/opt/iredmail/custom/openldap/conf.d/databases.conf`
+
+    OpenLDAP is configured to run one database for mail domains and accounts
+    by iRedMail Easy, if you want to run extra databases, you can add database
+    related settings in this file. for example:
+
+```
+database    mdb
+suffix      dc=my-ldap-suffix,dc=com
+directory   /var/lib/ldap/my-ldap-suffix.com
+
+rootdn      cn=Manager,dc=my-ldap-suffix,dc=com
+rootpw      {SSHA}...
+
+sizelimit   unlimited
+maxsize     2147483648
+checkpoint  128 3
+mode        0700
+
+index attr_1,attr_2,attr_3  eq,pres
+index attr_4,attr_5,attr_6  eq,pres
+```
+
 ### Nginx
 
 - `/opt/iredmail/custom/nginx/custom.sh`: a bash shell script for advanced

html/iredmail-easy.best.practice.html

@@ -30,6 +30,7 @@
 <li><a href="#passwords">Passwords</a></li>
 <li><a href="#custom-settings-used-by-softwares">Custom settings used by softwares</a><ul>
 <li><a href="#mariadb">MariaDB</a></li>
+<li><a href="#openldap">OpenLDAP</a></li>
 <li><a href="#nginx">Nginx</a></li>
 <li><a href="#postfix">Postfix</a></li>
 <li><a href="#dovecot">Dovecot</a></li>
@@ -312,6 +313,42 @@ under <code>/opt/iredmail/ssl/</code>:</p>
 max_connections     = 1024
 </code></pre>
 
+<h3 id="openldap">OpenLDAP</h3>
+<ul>
+<li>
+<p><code>/opt/iredmail/custom/openldap/schema/</code></p>
+<p>Extra LDAP schema files must be stored in this directory, owned by OpenLDAP
+daemon user and group with permission 0640.</p>
+</li>
+<li>
+<p><code>/opt/iredmail/custom/openldap/conf.d/global.conf</code></p>
+<p>Extra global settings should be stored in this file. For example, you can
+load extra LDAP schema file by adding line below:</p>
+<p><code>include /opt/iredmail/custom/openldap/schema/custom.schema</code></p>
+</li>
+<li>
+<p><code>/opt/iredmail/custom/openldap/conf.d/databases.conf</code></p>
+<p>OpenLDAP is configured to run one database for mail domains and accounts
+by iRedMail Easy, if you want to run extra databases, you can add database
+related settings in this file. for example:</p>
+</li>
+</ul>
+<pre><code>database    mdb
+suffix      dc=my-ldap-suffix,dc=com
+directory   /var/lib/ldap/my-ldap-suffix.com
+
+rootdn      cn=Manager,dc=my-ldap-suffix,dc=com
+rootpw      {SSHA}...
+
+sizelimit   unlimited
+maxsize     2147483648
+checkpoint  128 3
+mode        0700
+
+index attr_1,attr_2,attr_3  eq,pres
+index attr_4,attr_5,attr_6  eq,pres
+</code></pre>
+
 <h3 id="nginx">Nginx</h3>
 <ul>
 <li>