Mention that the box hostname cannot have an A record

guide.html

@@ -175,7 +175,7 @@ <h2 id="hostname">Your Box Has A Name</h2>
 
 	    			<p>Every machine connected to the Internet has a <b>name</b> and an <b>address</b>.</p>
 
-	    			<p>The <b>address</b>, an IP address, is like a telephone number. It&rsquo;s made up of numbers and is assigned to you by whoever provides Internet access to you.</p>
+	    			<p>The <b>address</b>, an IP address, is like a telephone number. It&rsquo;s made up of numbers and is assigned to you by whoever provides Internet access to your mail server (that&rsquo;s coming in the next section).</p>
 
 	    			<p>The name &mdash; called a <b>hostname</b> &mdash; is something you decide. It can be a domain name you own or any &ldquo;subdomain&rdquo; of a domain you own.</p>
 
@@ -185,6 +185,7 @@ <h2 id="hostname">Your Box Has A Name</h2>
 
 	    			<p>Your Mail-in-a-Box may handle the email for multiple domain names, but the box has a single name.</p>
 
+	    			<p>Your box&rsquo;s name <strong>CANNOT be a domain name that you intend to serve a website on</strong> from another web hosting service. We strongly suggest using a subdomain like <code>box</code>, as in the example above, so that you are able to use the main domain name for a website hosted from another web hosting service if you choose.</p>
 
 	    			<h2 id="machine">The Machine</h2>