“可以重定向随机网址”

I want to setup a website and to prevent DDoS attacks on it i am thinking of making multiple mirrors of front end and copy those domains to a txt file.

so that when user open "my-domain.com" it (php code picks a domain) and redirect it to "other-mirror.com"

I know i can use such codes

$urls = array('http://mirror-1.com',"http://mirror-2.com","http://mirror-3.com"); //specify array of possible URLs 

but not all clients want to mess up with codes so i am thinking to make a txt file which they can easily change according to requirement.