how to domain names work

[Tuttle]

To expand a bit on HAN's stuff, DNS is basically a tree. At the top, you have a root domain that doesn't actually have anything, but provides a starting point. At the next level down you have the "top level domains", including the generic (gTLD) ones (.com, .net, .org, .int, .mil, .info, .biz etc) and the country code (ccTLD) ones (.au, .nz, .uk, .us, .tv, .to, .cc etc). Under those you have second level domains (.example.com, .net.au etc), under those there are third level domains etc.

There is no box anywhere on the Internet which knows all the names -- each DNS server only knows about the part it's authoritative for. Looking up a full name therefore means getting info from a whole bunch of servers, starting (funnily enough) at the root.

The top of the DNS tree exists on a whole bunch of servers around the world which are presented to the Internet as 13 IP addresses -- ping A.ROOT-SERVERS.NET through M.ROOT-SERVERS.NET and you'll see what they are. Those servers only know about the TLDs, so they know that .com is handled by one set of servers and .au is handled by another. Then the servers which handle .com know about the second level domains under that (like example.com), but only enough to direct a query to the DNS servers that handle *.example.com.

So in order to get a domain name working on the Internet, you need to get it into one of those servers, and that's where the money/politics comes in. The top level domains are assigned by ICANN, and come about after a rather long process. You won't get .crus anytime soon.

Below that, however, each domain has an administrator (registry operator) which is responsible for setting policies about who can have domains under that domain, and for managing the DNS servers for that domain. Some registries do it themselves, others (like Verisign, who manage .com) only deal directly with registrars (like GoDaddy, or the separate registrar part of Verisign), and make end users deal with registrars instead. Some domains like .com and .net are really open, others have specific requirements (.mil is only available to the US military, .ca requires some sort of Canadian presence etc).

The upshot of all that is that in order to get a domain of the form yourstuff.theirstuff, you need to find out who the registry operator for theirstuff is, and do what they ask. That normally includes filling out forms and handing over money.

Hopefully that explains things a bit. If it rambles and gets confusing somewhere then let me know. Side note: Verisign is rather expensive if you want a domain in a gTLD. Shop around and go with someone else instead.