At the heart of the system are the top-level domains (TLDs)—these sit atop the whole domain name hierarchy. You might think these TLDs are largely immutable—rock solid objects that seldom change.

At the heart of the system are the top-level domains (TLDs)—these sit atop the whole domain name hierarchy. You might think these TLDs are largely immutable—rock solid objects that seldom change.

The principal job of a caching name server is to resolve a domain name, such as www.example.com, into an IP address. If it has no information about the domain name in its cache, it must track the ...