Transcript DNS and Internet Structure

DNS and Internet Structure
Monica Stoica, [email protected]
Papers used:
1. http://www.cpsr.org/dns/
2. http://www.cpsr.org/cpsr/nii/cyber-rights/web/current-domain.html
3.http://www.lantimes.com/handson/97/706a107a.html
4. http://www.internetstudies.org/members/holitscher/paris.html
5.http://hotwired.lycos.com/webmonkey/templates/print_template.htmlt?meta=/webmonkey/geek
talk/97/03/index4a_meta.html
6. http://www.mids.org/mn/806/dns.html
7. http://www.mids.org/mn/712/reht.html
8. http://www.shirky.com/writings/abuse_property.html
DNS
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The domain name system is a global network of
servers that translate host names like
www.hotwired.com into numerical IP (Internet
Protocol) addresses, like 204.62.131.129, which
computers on the Net use to communicate with
each other.
Without DNS, we'd all be memorizing long
numbers instead of intuitive URLs or email
addresses. And that wouldn't be much fun,
would it?
DNS history
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DNS was invented in 1984 to solve escalating
problems with the old name-to-address mapping
system.
The old system consisted of a single file, known as
the host table, maintained by the Stanford Research
Institute's Network Information Center (SRI-NIC).
As new host names trickled in, SRI-NIC would add
them to the table - a couple times a week. Systems
administrators would grab the newest version (via
FTP) and update their domain name servers.
Advantages of DNS
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But as the Net grew, the host table became
unwieldy. Though it worked fine for name-toaddress mapping, it wasn't the most practical or
effective way to update and distribute the
information. So DNS was invented.
The great thing about the domain name system is
that no single organization is responsible for
updating it. It's what's known as a distributed
database; it exists on many different name
servers around the world, with no one server
storing all the information.
Because of this, DNS allows for almost unlimited
growth.
DNS in US
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Each node on the tree represents a domain.
Everything below a node falls into its domain.
the machine chichi is part of the .us domain as
well as the .com domain.
If your site is outside the United States, the
organization that assigns domain names has its
own standards.
DNS: server and resolver
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A DNS server is just a computer that's running DNS
software. Since most servers are Unix machines,
the most popular program is BIND (Berkeley
Internet Name Domain), but you can find software
for the Mac and the PC as well.
DNS software is generally made up of two
elements: the actual name server, and something
called a resolver. The name server responds to
browser requests by supplying name-to-address
conversions. When it doesn't know the answer, the
resolver will ask another name server for the
information.
How It Works
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When you type in a URL, your browser sends a
request to the closest name server. If that server has
ever fielded a request for the same host name
(within a time period set by the administrator to
prevent passing old information), it will locate the
information in its cache and reply.
If the name server is unfamiliar with the domain
name, the resolver will attempt to "solve" the
problem by asking a server farther up the tree. If
that doesn't work, the second server will ask yet
another - until it finds one that knows. (When a
server can supply an answer without asking another,
it's known as an authoritative server.)
Time-out?
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Once the information is located, it's passed back to your
browser, and you're sent on your merry way. Usually this
process occurs quickly, but occasionally it can take an
excruciatingly long time (like 15 seconds).
In the worst cases, you'll get a dialog box that says the
domain name doesn't exist - even though you know it does.
This happens because the authoritative server is slow
replying to the first, and your computer gets tired of
waiting so it times-out (drops the connection). But if you
try again, there's a good chance it will work, because the
authoritative server has had enough time to reply, and your
name server has stored the information in its cache.
How to Configure DNS
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1.
2.
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There are two basic ways:
use your ISP's DNS server. Many ISPs
will let you do this.
set up a DNS server on your own network.
If you choose the first option you need to
do the followings:
How to set your own DNS server
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First, have your ISP inform the InterNIC that it is
providing both primary and secondary DNS
services for your organization.
Second, your ISP will give you the numeric IP
addresses of the primary and secondary DNS
servers, which you'll need to configure your users‘
TCP/IP stacks. You can do this by entering the
information manually either at the desktop or at
your Dynamic Host Configuration Protocol
(DHCP) server.
Setting up your server
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Finally, you need to tell your ISP about the DNS
records that you wish to publish to allow outside users
to interact with your network.
In addition, if you want to receive E-mail from the
Internet, you will need to have a Mail Exchange (MX)
record for your domain in your ISP's DNS database.
MX refers to a machine that accepts E-mail
connections for your domain.
An MX record has three parts: your domain name, the
name of the machine that will accept mail for the
domain, and a preference value.The preference value
lets you build some fault tolerance into your mail
setup.
Setting up the mail server
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Your domain can have multiple MX records,
such as the following:
Acme.com mail.acme.com 0 ; Acme.com
mail2.acme.com 10 ; and Acme.com mail.isp.net
100.
In this case, mail delivery will be attempted to
mail.acme.com first because it has the lowest
preference value. If delivery fails
mail2.acme.com will be tried next. If mail2 is
also down, mail will be sent to a relay host called
mail.isp.net, which in this case is at Acme's ISP.
A records
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the ISP has to set up some A records, which associate IP
addresses with computer names. Each of the computers
mentioned in your MX records needs an A record to
associate them with an IP address.
You may also want to set up A records for each of your
workstations if your users need to use ftp. This is because
some ftp sites perform a lookup to get the DNS name of the
machine from which they receive download requests. If the
machine has no name, the sites deny the request.
You'll also need A records for any public servers you
maintain. For example, if you have a World Wide Web
server, you'll need to have the ISP set up an A record
linking the name www.acme.com to the IP address of your
Web server.
Primary and Secondary DNS servers
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if your ISP does not provide name services or if you
need to have a DNS server at your site to support
internal networking applications, the first thing you
need to know is that you must have at least two
name servers--a primary and a secondary.
This is because the InterNIC will not grant you a
domain name unless there are at least two DNS
servers on the Internet with information about that
domain. Another reason for a second server is that
you really need the fault tolerance a second name
server can provide. If your one and only DNS
server goes down, users will be cut off from the
Internet.
Why bother having a DNS server on your LAN?
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First, if you are running IP network-based applications
inside your network that require users to connect to
internal machines by name, it is not a great idea to
advertise the names and addresses of these machines.
DNS can give hackers a map of your network, so setting
up an internal DNS server that does not publish
information to the world is a good idea.
Second, a DNS server inside your network lets you be the
master of your own domain. You can make changes,
additions, and deletions on your own schedule.
Finally, name resolution will be faster for your users
because your DNS server is probably not as heavily
loaded as your ISP's server.
One last note on having your own
DNS server:
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If you choose to administer the primary
name server yourself, keep in mind that
you'll have to maintain the DNS records .
InterNIC and the US government
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On June 5, 1998 the U.S. government issued a
White Paper on the Internet Domain Name System
(DNS). This White Paper is the U.S.
government's solution to expansion of the
organizational mechanisms supporting the
Internet DNS. It follows a Commerce Dept. Green
Paper that was issued 30 January 1998, which in
turn followed a commerce Request for Comments
(RFC) of 2 July 1997, which followed a presidential
directive of 1 July 1997 to ``privatize the domain
name system (DNS) in a manner that increases
competition and facilitates international
participation in its management.''
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Problem because:
The U.S. government never owned the DNS in the first
place, so it has no authority to privatize it.
It's true that the U.S. government has been partly funding
the administration of the GOV, EDU, ORG, NET, and
COM domains, through a series of grant agreements, most
recently through InterNIC, which is run by Network
Solutions, Inc. (NSI). The U.S. government can privatize
the administration of those domains (now known as generic
top level domains, or gTLDs) insofar as it funds their
administration.
But the U.S. government has never owned, for example,
the FR domain for France or the PE domain for Peru or the
HT domain for Haiti. And whole regions of DNS and IP
network number assignment authority have been delegated
to organizations such as RIPE for Europe and APNIC for
Asia-Pacific.
Why the mess?
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So why has the U.S. government now issued a White Paper
spelling out who is supposed to run the DNS? Because
everybody else had made such a mess of it.
Just as no one predicted the extended rapid growth of the
Internet or the social effects resulting from it, no one
adequately anticipated the organizational changes that
would be necessary to handle such growth. The DNS
itself was one of the several factors that combined around
1998 to make possible the rapid growth of the Internet.
Now that growth has made some kind of reform of the
DNS necessary. Unfortunately, the pre-existing
organization took too long to arrange for a change.
Problems with DNS
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This permitted various other organizations to
move in. They failed to produce a solution that
the Internet at large would agree to. The
resulting continuing lack of adequate DNS
organization led the U.S. government to step in.
Problems with DNS:
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lack of competition in domain name registration
confusion of trademarks and domains
One too common problem with DNS
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“Conflicts between trademark holders and domain
name holders are becoming more common.
Mechanism for resolving these conflicts are
expensive and cumbersome.''
This wording implicitly accepts that trademarks
are closely related to domains, which is a point
that has not been resolved. The White Paper
essentially delegates such resolution to WIPO
(World Intellectual Property Organization), which
indicates de facto acceptance of an equation of
trademarks and domain names.
Example
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In March 1997 IANA (the Internet Assigned Numbers
Authority) gave the HT domain for Haiti briefly to one
registrar: REHRED and then a week later to another
registrar FOCUS DATA
The latter change of registration was made without any
warning and without any of the due process spelled out in
IANA's own published guidelines, RFC 1591 of March
1994, http://ftp.internic.net/rfc/rfc1591.txt>, ``Domain
Name System Structure and Delegation'' by J. Postel.
The developments since then (as of the time the paper was
written) follow:
The Haiti case – IANA mistake
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How many subdomains have been registered under the top
level domain HT? Zero; none at all.
Has any agreement been reached among the various parties
in Haiti regarding who should be the registrar of the HT
domain? Not as of this writing.
Has the Haitian government changed or clarified its
position? No, it has not. Meanwhile, the prime minister has
resigned (for unrelated reasons), making it difficult even to
find out who would be in charge of such a position
Has IANA changed its position? No, it has not.
“The IANA has asked the parties is Haiti to work together
to come up with a commonly agreed on plan for the
management of the .HT top level domain. As yet, we have
not received any such plan or proposal for such a plan. “
Other cases – laugh or cry?
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Volkswagen suing to have control over Vw.org
Priceline suing Expedia over Priceline's patented "name
your own price" business model
Amazon suing Barnes and Noble for copying Amazon's
"One-Click Ordering."
trademark lawyers, with Etoys convincing a California
court to issue a preliminary injunction against etoy.com, the
Swiss art site, because the etoy.com URL might "confuse"
potential shoppers. Never mind that etoy.com registered its
URL years before Etoys existed: etoy has now been
stripped of its domain name without so much as a trial, and
is only accessible at its IP address
(http://146.228.204.72:8080).
Last case …
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Most recently, MIT's journal of electronic
culture, Leonardo, is being sued by a company
called Transasia which has trademarked the
name "Leonardo" in France, and is demanding a
million dollars in damages on the grounds that
search engines return links to the MIT journal,
in violation of Transasia's trademark…