The root node of DNS has a
The DNS tree is restricted to 127 levels of depth so you could
. is used to mark a domain as absolute eg;
Behind the scenes, a full domain name would be
Some websites, or perhaps more accurately the load balancers and proxies in front of them, don't acknowledge the existence of such a thing.
One high profile example is Amazon. If you visit https://amazon.com.,
you'll see a blank page with the title
x. Note the period on the end of the URL to see this
issue in effect.