Plissken wrote:
I'm speaking genrically, as opposed to a specific ISP.
Its actually concerning a .ac.uk domain.
They'll be a name/dns server that hosts your info. When someone wants plissken.ac.uk, they'll talk to that server and say "what ip is it, plz?". If someone wnats what.the.hell.plissken.ac.uk, they'll talk to the same server, as it's the most they know about. That server can either redirect them to another dns server, who knows where to find hell.plissken.ac.uk, or the server itself will know (because you told it).
Either way; it's kinda "free". As long as you can change the dns entries somehow, you can add as many silly sub domains as you like.