diff --git a/en_US/iredmail-easy/2-iredmail-easy.best.practice.md b/en_US/iredmail-easy/2-iredmail-easy.best.practice.md
index 19d7a11e..641030e1 100644
--- a/en_US/iredmail-easy/2-iredmail-easy.best.practice.md
+++ b/en_US/iredmail-easy/2-iredmail-easy.best.practice.md
@@ -253,13 +253,15 @@ multiple files.
 For other settings, Postfix is configured to load the one under
 `/opt/iredmail/custom/postfix/` first (this should be maintained by you), then
 another one from `/etc/postfix/` (maintained by iRedMail Easy and you should
-NOT update them).
+NOT update them). If rule defined in first one matches, Postfix will skip the
+second file.
 
 For example, Postfix loads 2 files for HELO access check:
 
 - `/opt/iredmail/custom/postfix/helo_access.pcre`: You can add custom HELO
    access rules in this file, or add rule to override the one defined in
-   `/etc/postfix/helo_access.pcre`.
+   `/etc/postfix/helo_access.pcre`. If access rule in this file matches,
+   Postfix will ignore the second (and all the rest) files.
 - `/etc/postfix/helo_access.pcre`: This file is maintained by iRedMail Easy,
   you should NOT modify it.
 
diff --git a/html/iredmail-easy.best.practice.html b/html/iredmail-easy.best.practice.html
index ed541301..e4d46c8e 100644
--- a/html/iredmail-easy.best.practice.html
+++ b/html/iredmail-easy.best.practice.html
@@ -379,12 +379,14 @@ multiple files.</p>
 <p>For other settings, Postfix is configured to load the one under
 <code>/opt/iredmail/custom/postfix/</code> first (this should be maintained by you), then
 another one from <code>/etc/postfix/</code> (maintained by iRedMail Easy and you should
-NOT update them).</p>
+NOT update them). If rule defined in first one matches, Postfix will skip the
+second file.</p>
 <p>For example, Postfix loads 2 files for HELO access check:</p>
 <ul>
 <li><code>/opt/iredmail/custom/postfix/helo_access.pcre</code>: You can add custom HELO
    access rules in this file, or add rule to override the one defined in
-   <code>/etc/postfix/helo_access.pcre</code>.</li>
+   <code>/etc/postfix/helo_access.pcre</code>. If access rule in this file matches,
+   Postfix will ignore the second (and all the rest) files.</li>
 <li><code>/etc/postfix/helo_access.pcre</code>: This file is maintained by iRedMail Easy,
   you should NOT modify it.</li>
 </ul>