通过启用 mod_rewrite 和 .htaccess httpd.conf,然后将此代码放在您.htaccess的DOCUMENT_ROOT目录下:
Options +FollowSymLinks -MultiViews
# Turn mod_rewrite on
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} ^(www\.)?a\.fr$ [NC]
RewriteRule ^ http://a.com%{REQUEST_URI} [R=301,L]