如果指令在 apache VirtualHost conf 中不起作用，則顯示“無效命令”

為什麼？？

<VirtualHost *:80>
       ServerAdmin admin@mydomain.com
       DirectoryIndex index.php
       <If "%{SERVER_PROTOCOL} != 'HTTPS'">
           Redirect / https://www.mydomain.com:443/
       </If>
.....
</VirtualHost>

保存，然後重新啟動：

sudo /etc/init.d/apache2 restart
Syntax error on line 4 of /etc/apache2/sites-enabled/000-default:
Invalid command '<If', perhaps misspelled or defined by a module not included in the server configuration
Action 'configtest' failed.
The Apache error log may have more information.
  ...fail!

“如果”不是 Apache 理解的（在 2.3 版之前）。你可能應該看看 mod_rewrite

RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteRule ^/(.*) https://example.com:443/$1 [R,L]

要找到您的 apache 版本，您可能可以使用：apache2 -v

引用自：https://serverfault.com/questions/340977