Mention how to disable postscreen service.

en_US/howto/1-enable.smtp.auth.on.port.25.md

@@ -12,6 +12,7 @@ below to enable it.
     connection, you may try another tutorial instead:
     [Allow internal network devices to send email with insecure connection](./additional.smtp.port.html)
 
+* Disable postscreen service first: [Disable postscreen service](./enable.postscreen.html#disable-postscreen-service).
 * Find comment out settings in Postfix config file `/etc/postfix/main.cf`
   (Linux/OpenBSD) or `/usr/local/etc/postfix/main.cf` (FreeBSD):
 

en_US/howto/enable.postscreen.md

@@ -30,6 +30,31 @@ Important notes:
   (FreeBSD) to check the DNSBL servers it enabled, you're free to remove some
   of them (or add new ones) if you want.
 
+## Disable postscreen service
+
+If your iRedMail already have postscreen service enabled, it's easy to disable
+it by following steps below.
+
+* Open file `/etc/postfix/master.cf`, find lines below (usually they're first
+  few lines in this file):
+
+```
+#smtp      inet  n       -       -       -       -       smtpd
+smtp      inet  n       -       -       -       1       postscreen
+smtpd     pass  -       -       n       -       -       smtpd
+```
+
+* Uncomment first line, comment out the other 2 lines:
+
+```
+smtp      inet  n       -       -       -       -       smtpd
+#smtp      inet  n       -       -       -       1       postscreen
+#smtpd     pass  -       -       n       -       -       smtpd
+```
+
+* Now restart or reload Postfix service. That's it. No need to modify any
+  setting in `/etc/postfix/main.cf`.
+
 ## See Also
 
 If you don't want to use postscreen service, you can [enable DNSBL service](./enable.dnsbl.html)

html/enable.postscreen.html

@@ -20,6 +20,7 @@
 <ul>
 <li><a href="#enable-postscreen-service">Enable postscreen service</a><ul>
 <li><a href="#enable-postscreen-service_1">Enable postscreen service</a></li>
+<li><a href="#disable-postscreen-service">Disable postscreen service</a></li>
 <li><a href="#see-also">See Also</a></li>
 <li><a href="#references">References</a></li>
 </ul>
@@ -50,6 +51,30 @@ service.</p>
   (FreeBSD) to check the DNSBL servers it enabled, you're free to remove some
   of them (or add new ones) if you want.</li>
 </ul>
+<h2 id="disable-postscreen-service">Disable postscreen service</h2>
+<p>If your iRedMail already have postscreen service enabled, it's easy to disable
+it by following steps below.</p>
+<ul>
+<li>Open file <code>/etc/postfix/master.cf</code>, find lines below (usually they're first
+  few lines in this file):</li>
+</ul>
+<pre><code>#smtp      inet  n       -       -       -       -       smtpd
+smtp      inet  n       -       -       -       1       postscreen
+smtpd     pass  -       -       n       -       -       smtpd
+</code></pre>
+
+<ul>
+<li>Uncomment first line, comment out the other 2 lines:</li>
+</ul>
+<pre><code>smtp      inet  n       -       -       -       -       smtpd
+#smtp      inet  n       -       -       -       1       postscreen
+#smtpd     pass  -       -       n       -       -       smtpd
+</code></pre>
+
+<ul>
+<li>Now restart or reload Postfix service. That's it. No need to modify any
+  setting in <code>/etc/postfix/main.cf</code>.</li>
+</ul>
 <h2 id="see-also">See Also</h2>
 <p>If you don't want to use postscreen service, you can <a href="./enable.dnsbl.html">enable DNSBL service</a>
 instead, it helps a lot too, but less effective than postscreen service.</p>

html/enable.smtp.auth.on.port.25.html

@@ -32,6 +32,7 @@ connection, you may try another tutorial instead:
 <a href="./additional.smtp.port.html">Allow internal network devices to send email with insecure connection</a></p>
 </div>
 <ul>
+<li>Disable postscreen service first: <a href="./enable.postscreen.html#disable-postscreen-service">Disable postscreen service</a>.</li>
 <li>Find comment out settings in Postfix config file <code>/etc/postfix/main.cf</code>
   (Linux/OpenBSD) or <code>/usr/local/etc/postfix/main.cf</code> (FreeBSD):</li>
 </ul>