DNS or Domain Name System, presents friendly names for computer addresses that people can read and remember, and then resolves them to IP addresses (numbers) for computers to use over the Internet and within networks. So instead of an IP address such as 204.34.174.78, you see a memorable domain name such as broccoli.com in a browser address or location field, such at the top in Netscape's Navigator or Microsoft's Internet Explorer.

On Windows 95, DNS provides a distributed database containing a hierarchical naming system for identifying hosts (computers) on the Internet.

DNS requires static configuration of IP addresses (numbers) for name-to-address mapping. Although to determine a domain name your system can have a dynamically assigned IP address.

The DNS database is a tree structure called the domain name space, where each node of domain is named and can contain subdomains. The domain name identifies the domain's position on the database in relation to its parent domain, with a period (.) separating each part of the name for the network nodes of the DNS domain.

A example of an IP address you may see in your browser location field, is 255.255.255.255; four numbers separated by three dots, hence the name "dotted quad".

The root of the DNS database is managed by the Internet Network Information Center. The top-level domains were assigned by country and organization following the International Standard 3166. Two-letter and three letter abbreviations are for countries and the others as shown below:

DNS domain name       Type
.com      Commercial (real.com for Real Networks)
.edu       Educational (harvard.edu for Harvard University)
.gov       Goverment (nsf.gov for National Science Foundation)
.org        Noncommercial (fidonet.org for Nidonet)
.net        Networking organizations (MPL.net for MPLNET)
there are also domains based on country.

DNS uses the client-server model, where Domain Name Servers contain information about a portion of the DNS database and make this data available to clients, called resolvers, which query the name server across the network. DNS name servers are programs that store information about parts of the domain space called zones.

The administrator for a zone sets up name servers which contain the database files with all the resource records describing all hosts in their zones. DNS resolvers are clients using name servers to gain information about the domain name space.

All the resolver software needed for using DNS is installed with Microsoft TCP/IP. To see this in Win95, go to:

1. Start
2. Settings
3. Control Panel
4. Network
5. Configuration tab
6. Click on TCP/IP
7. Click on the Properties button

Click on DNS configuration tab

(Note: If you click on WINS configuration tab you'll find it has been disabled - this is another way besides DNS to accomplish the same things. WINS provides name-to-address mapping dynamically and is said to require less administration.)

Always click Cancel when you finish looking at this, unless you want to reinstall your networking software!

As previously mentioned, DNS presents friendly names you can read and remember, and then resolves them to IP addresses for computers to use over the Internet/networks. If a local name server doesn't have the data requested in a query (to resolve an address), it sends back names and addresses of other name servers which might. The resolver then continues its search for the exact name/address it needs. Name servers continuously cache information received about the domain name space, so this process is fast.

TCP/IP uses IP addresses to contact other computers, but humans prefer to use host names. MS TCP/IP includes the DNS resolver functionality used by other common connectivity sw such as Net Bios over TCP/IP, Windows Sockets, FTP, and Telnet. DNS is also used in UNIX based networking for standard naming conventions (in addition to HOSTS file) to contact "foreign hosts."

Resolving of DNS accounts for why you see "Microsoft.com" in your browser's location field instead of the IP address for the machine hosting the site such as "204.74.25.71" or something similar.


Questions

How do you find out where a server is located in the world via the IP address or the domain name? Say, for example if you have a web site and your log information lists the IP address (204.34.174.78), not the domain name (broccoli.com). How do you look it up?

Primarily, most Networkers use InterNIC's tools at http://rs.internic.net/cgi-bin/itts/ Take a look at the variety of tools on InterNIC's site. InterNIC is the company responsible to register domain names, and keep track of them. Information located on InterNIC's website can be out of date by as much as a year. If you need to know who owns a block of IP addresses locate that information on InterNIC, then contact the support staff directly for verification.

If you just have one IP address you need to know the domain name for (or vice versa), run ping from a DOS-prompt (in Windows/NT) with the -a specified.
example:
ping -a 205.163.213.237
Ping returns the name of the IP address if it is a registered host.



On a DOS based machine you can run nslookup, which resolves IP addresses into domain names, provided they are registered.
example:
Type nslookup and you'll get a prompt
Type set type=any (return)
Then type the domain name such as sun.com (return)
This will list all domain information currently available to a DNS query

Then run whois with the resultant information.
example:
whois 207.68.157.58

(type exit to return to DOS)

If you're trying to obtain demographics, these numbers can be misleading. You may be logging an ISP, or a Tier 1 machine, which isn't an accurate reflection of where the hit orginated. There are a lot of unregistered machines.

How do I see how good my connection is, or how long it takes for my system to contact another computer? Can I use a DNS or an IP address to do this with?

A tracert run at DOS or traceroute run on UNIX will provide information about how long it takes your system to reach a specific targeted machine, and you can use either a Domain name such as Apple.com or an IP address to run this network test. It's easy!
example:
For Windows 95 or NT users, go to Start, Run, and type:
tracert microsoft.com
and a DOS session should open and display something like the following:

Tracing route to microsoft.com [207.68.137.56]

over a maximum of 30 hops:



  1   <10 ms   <10 ms    10 ms  abc.xyx.net [200.10.34.1] 

  2     *        *        *     Request timed out.

  3     *        *        *     Request timed out.

  4     *        *        *     Request timed out.

  5     *        *        *     Request timed out.

Tracert is a good test to see what your computer and ISP's connection speed is to a particular host computer.

The test times are in milliseconds. Each timed column shows how many milliseconds it took for the test to reach a computer linked via the network to reach the target computer or host.

If the timed columns show an asterisk, '*', this shows that the test connection timed out. The name or address column might show error messages such as "Request timed out", instead of the domain name or IP address. Asterisks and messages may indicate a very poor connection, or may show that the server, which is still registered in a DNS lookup table but not currently available - is down.

If you need to store the information in a file, use the following command:
tracert DNSname.com > trace.txt. Then open the trace.txt in any text editor.

For MacOS users there are various route tracing programs. The MacOS based application WhatRoute is available at most shareware related web sites. Try the Hyperarchive site at:
http://hyperarchive.lcs.mit.edu/cgi-bin/NewSearch?key=traceroute.


What is the future of DNS?

The Federal Goverment agency which oversees DNS, the US Department of Commerce, released a proposal to privatize Internet Domain Registration, published by the National Telecommunication and Information Adminstration. at http://www.ntia.doc.gov/ntiahome/press/013098dnspro.htm

gTLDs stands for "generic Top Level Domains", in this use generic means anyone can use it worldwide.

These are the seven new proposed top-level domains:

• .firm - businesses, or firms
  
• .store or .shop - businesses offering goods to purchase
  
• .web - entities emphasizing activities related to the WWW
  
• .arts - entities emphasizing cultural and entertainment activities
  
• .rec - entities emphasizing recreation/entertainment activities
  
• .info - entities providing information services
  
• .nom or .per - those wishing individual or personal nomenclature
  
  
  See the following links for more complete information on the changing domain names-
  
  
  
• The Federal Government's

  Green Paper
  
  

• The Electronic Frontier Foundation's EFF comments on US Commerce Dept. (NTIA) proposal regarding future management of the Internet Domain Name System (DNS) March 23, 1998
  
  
• The Generic Top Level Domain Memorandum Of Understanding
  
  
• The Internet Society and their response to the Federal Green Paper http://www.isoc.org/internet/news/greenpaper.shtml
  
  
• The Information Sciences Institute
  
  See http://internic.net or their partner http://www.alldomains.com/ for the latest info on domain names. AllDomains is selling domains .PER, .NU and .TO.
  
  So far InterNIC is not accepting pre-registrations for the new Top Level domains, which are scheduled to begin implementation in April 1998 according to J. Beckwith Burr, associate administrator, NTIA, Office of International Affairs (OIA).
  
  Judge rules domain fees illegal April 9, 1998, 11:20 a.m. PT
  
  Lots of debate on Domains in April of 1998 - That's all for now!