I want to redirect all of my users who go to www.mywebmailserver.com to webmail.mywebmailserver.com. I have learned that from my googling, there are 2 popular ways to do it in apache web server. First, by using mod_rewrite and second, I can use redirect. The latter is the simplest. So I chose it. :)
Put this in vhost container.
NameVirtualHost www.mywebmailserver.com <virtualhost www.mywebmailserver.com> ServerName www.mywebmailserver.com Redirect 301 / http://webmail.mywebmailserver.com/ </virtualhost>
In Mageia 4, the file is located in /etc/httpd/conf/vhosts.d and the file name is 00_default_vhosts.conf
That's it. Restart or reload apache for the changes to take effect.