diff --git a/en_US/installation/0-setup.dns.md b/en_US/installation/0-setup.dns.md
index fccdfdce..5e363e98 100644
--- a/en_US/installation/0-setup.dns.md
+++ b/en_US/installation/0-setup.dns.md
@@ -201,10 +201,10 @@ tag. Note that the same identity can have multiple identifiers.
 
         * On some Linux/BSD distribution, you should use command `amavisd-new`
           instead of `amavisd`.
-        * If it complains `/etc/amavisd.conf not found`, please
+        * On CentOS, if it complains `/etc/amavisd.conf not found`, please
           run the command with path to its config file. For example:
 
-            `amavisd -c /etc/amavisd/amavisd.conf showkeys`
+          ```amavisd -c /etc/amavisd/amavisd.conf showkeys```
 
 ```bash
 # amavisd showkeys
diff --git a/html/setup.dns.html b/html/setup.dns.html
index ab9b2a48..d182883f 100644
--- a/html/setup.dns.html
+++ b/html/setup.dns.html
@@ -217,11 +217,10 @@ tag. Note that the same identity can have multiple identifiers.</p>
 <ul>
 <li>On some Linux/BSD distribution, you should use command <code>amavisd-new</code>
   instead of <code>amavisd</code>.</li>
-<li>If it complains <code>/etc/amavisd.conf not found</code>, please
+<li>On CentOS, if it complains <code>/etc/amavisd.conf not found</code>, please
   run the command with path to its config file. For example:</li>
 </ul>
-<pre><code>`amavisd -c /etc/amavisd/amavisd.conf showkeys`
-</code></pre>
+<p><code>amavisd -c /etc/amavisd/amavisd.conf showkeys</code></p>
 </div>
 </li>
 </ul>