IP Addresses/Domain Names    (Day 3/4)

TOPICS:

• IP addresses.
• Domain names.
• Assignment: Reading assignment - Due Thursday, September 5.

IP Address

Every machine (more specifically, every computer device) on the Internet must have it's own  IP address . Recall, IP stands for Internet Protocol.  Each computer on the Internet has a unique IP number that operates at its Internet address.  This is how statistics are gathered and emails get delivered to the proper destination. The count is based on the number of IP addresses in use that year.

An IP address consists of 32 bits or four bytes. (A byte consists of eight bits.) The largest possible eight-bit number is 255. Each IP address consists of 4 pieces -- 8 bits each -- meaning each piece is a number between 0 and 255.

• IP addresses provide universal addressing across all of the networks of the Internet.
• An IP address is split into four pieces.
• The pieces of the IP address are separated by dots (.).
• An IP address contains a network part and a host part.
• There are three main classes of addresses: class A, class B, class C.
• IP addresses are assigned by the Network Information Center (NIC)

IP Address Classes and Their Formats:

• Class A   Addresses are for large networks with many devices
• Class B   Addresses are for medium-sized networks
• Class C   Addresses are for small networks (fewer than 256 devices).

Maricopa CC District's IP address is:    140.198.0.0    This is then broken up between the schools.

One of MCC's is:        140.198.64.15

The machine in my office is:     140.198.64.170    here at MCC the 170 must be unique (machine number)

When I log in from home it is:    128.0.0.0

The following list summarizes how many hosts each class network can support:

• class A networks can have millions (~16M) of hosts.
• class B network can have thousands (~65,000) of hosts
• class C network is composed of fewer than 254 hosts.

The more machines that share the same protocol, the more powerful the resulting communication medium.

The current IP address design (IPv4) doesn't support the rapid growth of the Internet. Some predict that within the next couple of years, all class B addresses will be exhausted. As a result a new system called Internet Protocol Next Generation (IPng) is being designed that will extend the capacity of the Internet by many orders of magnitude. [ document "IP Next Generation Overview"] Their goal is to create 128-bit numbers rather than using the current 32-bit numbers. That would mean 16 groups of 3 numbers -- that may last us a while.

IP addresses may be either STATIC or DYNAMIC. The IP address is "static" if a permanent address is assigned to a connected Internet device. It is "dynamic" if each time the device is connected to the Internet is it assigned an address from the ISP's (Internet Service Provider's) pool of IP addresses.

Example: My computer here at MCC has a permanent IP address so the address is "static" but when I log on to the Internet through AOL it issues me a IP at the time of connection and that address is "dynamic".

List of IP Numbers by Class:    http://www.flumps.org/ip/

Domain Names

DNS  (Domain Name Service) is a distributed hierarchical system for resolving host names into IP addresses.

What is the relationship between IP addresses and domain names? IP addresses are 32-bit numbers whereas domain names are easy to remember symbolic strings.

Examples: microsoft.com, whitehouse.gov, pbs.org

How does a computer use this since it needs to work with IP addresses? There is a program called a resolver that takes care of the translation. This program converts a symbolic names to its corresponding IP addresses -- remember that each symbolic names has a unique IP address.

DNS has a  root domain  at the top of the domain hierarchy.

Directly under the root domain are the  top level domains . There are two basic types of top level domains -- geographic and organizational.

mc.maricopa.edu  is a Domain Name.

  Organization(s):  mc, maricopa

Organization Type:  edu

The network maintained by Mesa Community College,  mc , which in turn is part of the Maricopa County Community College District network,  maricopa , which is itself a U.S. educational institution, edu .

Most popular top level domains are: com, edu, net, mil, org, and gov.

In the U.S., each system belongs to either an organizational domain or a geographical domain, not both.

Map country codes to countries. [http://www.immigration-usa.com/country_digraphs.html]

DNS allows a machine to go by many names (i.e. "aliases"). This allows system administrators to give descriptive names to their servers, but at the same time keep them easily accessible to the clients.

Is your domain name taken --- check it out:   -   http://www.igoldrush.com/

Where can you register a domain name?  

        --->  Here is a list of places who can do it:    http://www.igoldrush.com/links2.htm