Alias /postfixadmin /usr/share/postfixadmin

<Directory /usr/share/postfixadmin/>
   AddDefaultCharset UTF-8

   <IfModule mod_authz_core.c>
     # Apache 2.4
     <RequireAny>
        Require all granted
     </RequireAny>
   </IfModule>
   <IfModule !mod_authz_core.c>
     # Apache 2.2
     Order Deny,Allow
     Allow from 127.0.0.1
     Allow from ::1
     Allow from 192.168.1.0/24
   </IfModule>
</Directory>