Here's a silly question you can probably answer. What if I wanted to make a static local copy of a DNS server for the potential event that something bad happens (like terrorists crash it, etc, or the UN starts taxing, who knows.)
How big would that file be? And, or, is there some easy automated way for me to build just a snapshot of IP addresses of my bookmark list? Obviously, over time the static nature of it would deteriorate its accuracy, but at least for some sites it would keep working.
For example, if the UN controlled the root servers and they wanted to insert a filter server in front of FreeRepublic, couldn't they just insert their server in the DNS pointers instead of directly to FR's?
Huge. The Domain Name Service is the largest distributed database in the world. Even your ISP's name servers don't know about every hostname on every domain.
If you want to surf to www.cnn.com (for example), typically your ISP name server will query the root name servers to find out the address of the authoritative name server for cnn.com (the one which is guaranteed to know all about that domain). Then it goes to the authoritative name server to get the address of the host you want to contact (www). Then it gives that address to your PC and away you go.
As you can see, there are several servers involved, none of which are under the control of any one entity. Domains are required to maintain more than one name server, and (if they're smart) put them on different subnets, such that if the path to a particular subnet is wiped out there is still a path to a backup somewhere.
And, or, is there some easy automated way for me to build just a snapshot of IP addresses of my bookmark list? Obviously, over time the static nature of it would deteriorate its accuracy, but at least for some sites it would keep working.
You can maintain your own list of host addresses (the file is /etc/hosts on Unix platforms, and I think it's "hosts.txt" in some Windows system directory on Win32 systems) but that's purely a manual exercise. That's the problem that DNS was developed to fix.
Another problem is that your list of hosts could go obsolete very quickly. While it's not very feasible for a net admin to move established hosts around (www.cnn.com will probably stay where it is for a long while), they do add new hosts from time to time. The name server cache on local servers expires occasionally, so they're always checking back with the authoritative name servers to make sure they have current information.
For example, if the UN controlled the root servers and they wanted to insert a filter server in front of FreeRepublic, couldn't they just insert their server in the DNS pointers instead of directly to FR's?
Easily. They could redirect all requests for www.freerepublic.com to one of their servers which might put a "sorry, this domain is unavailable" screen on your browser; or maybe even a mock FR site which presents their own views.
You may remember, a couple of years ago FR had some problems with their provider's authoritative name servers getting out of whack. Unless you had FR's IP address (209.157.64.200 and .201) saved somewhere, you couldn't get to it.