content/blog/mail_server_alpine_postfix_dovecot_tutorial.md: start amavis section + add service commands

content/blog/mail_server_alpine_postfix_dovecot_tutorial/index.md

@@ -726,10 +726,11 @@ namespace inbox {
 
 You can set the `auto = create` option for any mailbox you want to be auto-created for users.
 
-Now restart Dovecot. Keep an eye on terminal output, as if there's a configuration error, you'll get an error message
+Now enable and start the Dovecot service. Keep an eye on terminal output, as if there's a configuration error, you'll
-when restarting.
+get an error message when restarting.
 
-    # rc-service dovecot restart
+    # rc-update add dovecot default
+    # rc-service dovecot start
 
 # Use a local email client
 
@@ -872,6 +873,11 @@ OpenDKIM is an open-source implementation of DKIM signing and authentication. Yo
 
 You may also want `opendkim-doc` for documentation.
 
+Enable the service:
+
+    # rc-update add opendkim default
+    # rc-service opendkim start
+
 Add the `postfix` user to the `opendkim` group:
 
     # adduser postfix opendkim
@@ -1218,6 +1224,16 @@ suggestions.](https://wiki.list.org/DEV/DMARC)
 
 # Amavis
 
+Amavis is a high-performance interface between MTAs and content checkers, such as virus scanners and spam filters. We
+will use Amavis as a Postfix content filter for virus scanning and spam filtering, with ClamAV and SpamAssassin
+respectively.
+
+Install Amavis and enable the service:
+
+    # apk add amavis
+    # rc-update add amavisd default
+    # rc-service amavisd start
+
 # Miscellaneous suggestions
 
 You may want to get your domain whitelisted on [dnswl.org](https://www.dnswl.org/), an email whitelist service where