[Xitami] IP numbers,etc.

[Paul Reid]

>  is it possible to give a page a more durable address - say, a URL
> or a domain name?

"Easy way": get a Fixed IP address. That's how we used to do all
internet machines. Each school was given a block of IP numbers. At
each school a"hostmaster" person or office would assign IP numbers
to new machines, and that IP number is entered in the machine's TCP
configuration file.

Since people prefer typing names instead of numbers, a system
evolved so if you type a name where an IP number would be, the
computer contacts a name-server to translate the name to an IP
number. "DNS" is a Dynamic Name Server (it can be updated
constantly, compared to older systems that were harder to update).
Generally each school maintains a DNS server and contracts another
school to be a back-up in case of trouble.

Al Gore commercialized the InterNet, but ISPs follow the same
pattern. They have a block of IP addresses they can give to
customers, and maintain DNS servers to translate names to numbers.

So you get an IP number, you reserve names for your domain and each
machine, you enter those names and IP numbers in a DNS server. Then
anybody who types the name of your machine will get the IP number
and connect to your machine. Easy.

The DNS server has to be easy to find and very reliable. It is
possible to run your own DNS server but you usually want to have
someone else with an established DNS system to handle it.

A problem with that is: the world is running out of IP numbers. And
anyway it is silly to permanently assign an IP number to a dial-up
user who only needs it a few hours a month. A dial-up service with
10,000 customers often has only 1,000 modems and so only needs 1,000
IP addresses. You get an IP address when you connect, and you lose
it when you disconnect, and next time you will probably get a
different IP number.

Another side is: cable-modem/DSL is "always on" but the ISP may need
to change IP numbers as they grow their system. Customers won't know
how to change their IP numbers. So they ask you to use DCHP, a
protocol that assigns IP numbers when you connect and can re-assign
if needed. (PoET is another variant of DCHP-like service, adapted
for spread networking.) Or to be honest: many ISPs deliberately
change IP numbers from time to time, just to make it hard for you to
run a busy server on a "home" account, so you will pay more for a
Business account.

There is a way to get around impermanent IP numbers. Others have
pointed you to the Dynamic DNS services. When you start your
machine, or your IP number changes, your machine tells them what
your IP number is today. Their DNS server is registered (with the
master DNS systems) to be the DNS server for your domain. When
people type your machine name, they end up at that DNS server which
gives them the latest IP number for you. It is not perfect:
sometimes intermediate DNS servers hold old info longer than they
should. But as you see, it works good for jon and Marcio.

http://www.zoneedit.com/doc/dynamic.html?

Yes, Dynamic Dynamic Name Server sounds redundant. But in fact there
is an extra level of "dynamic" in these systems. Traditional DNS is
managed by a hostmaster, who can make changes any time she feels
like it. DDNS allows users to update info very frequently without
human attention.

For many reasons, it is often better to off-load the whole chore to
a commercial Web Host: someone with a fast connection, established
DNS, and racks of servers they rent-out. Do-it-yerself can be fun,
and sometimes the best way, but a goos web host service can be more
reliable and possibly cheaper all considered.

 -PRR