1479
Welp that answers a lot of why all .ml are down
(i.imgur.com)
This is a most excellent place for technology news and articles.
They don't know unless the DNS server tells them. For example, a very popular webhost Akamai uses a complex DNS + web hosting suite (DNS edgesuit to be exact) to send that type of data to the web servers. It can also allow for many many other features.