Add Sieve Port (4190) to Firewall Instructions

guide.html

@@ -229,7 +229,7 @@ <h3>Locate the machine&rsquo;s IP address</h3>
 
 	    			<h3>Firewall settings</h3>
 
-	    			<p>If your machine is behind a hardware firewall (or virtual equivalent, such as an AWS security group), ensure that the following ports are open: 22 (SSH), 25 (SMTP), 53 (DNS; must be open for both tcp &amp; udp), 80 (HTTP), 443 (HTTPS), 587 (SMTP submission), 993 (IMAP) and 995 (POP). It doesn&rsquo;t hurt to block other ports, but your box will take care of that itself by configuring a software firewall on the machine itself.</p>
+	    			<p>If your machine is behind a hardware firewall (or virtual equivalent, such as an AWS security group), ensure that the following ports are open: 22 (SSH), 25 (SMTP), 53 (DNS; must be open for both tcp &amp; udp), 80 (HTTP), 443 (HTTPS), 587 (SMTP submission), 993 (IMAP), 995 (POP) and 4190 (Sieve). It doesn&rsquo;t hurt to block other ports, but your box will take care of that itself by configuring a software firewall on the machine itself.</p>
 
 
 	    			<h2 id="glue-records">Domain Name Configuration &mdash; Glue Records</h2>