Domain Names, IP Addresses and URLs

COMP1260 > Understanding the Internet

Introduction Like the places where we live have physical addresses (1-123 Anystreet, Winnipeg, Manitoba), we also have addresses that identify us on the internet (IP Addresses). Websites we visit on the internet also have their own addresses. These sites are identified by their Uniform Resource Identifiers (URLs) and their Domain Name postfixes such as .com, .org, .net, or country code domains like .ca, .de, and .uk.

...by students The first programming I had ever done was on a VIC-20. This was my first "personal computer". I was able to write small programs and filled the 20k of RAM very quickly. How excited I was to get a Commodore-64 the following Christmas. It came with a tape drive. Not only did I have more RAM, I was able to save my work for refinement. A year later my high school introduced new courses called Computer Awareness. In these courses we discussed and anticipated what impact these new tools might have on our society, discovered we could connect to other computers over phone lines, and learned how to program. For programming we used the new Apple IIE and were able to save our work on floppy disks that were read much more quickly than my tape drive. After graduation I did not do any programming until I came to University 20 years later. Things had changed so much. My cell phone had more memory on its micro sd card than all the computers in my school division when I graduated. I was introduced to my first programming language since Apple basic and found that the excitement for programming I had in my youth was still there. I switched from Electrical Engineering to Computer Science and am currently in my 3rd year. </td> </tr> </table> IP Addresses Every computer that communicates over the Internet is assigned an IP address by an Internet Service Provider (ISPs). This uniquely identifies the device and distinguishes it from other devices on the Internet. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be 0-255 (8 bit sequence). For example 169.192.0.1 can be an IP address. An IP address consists of two parts, one identifying the network and one identifying the node, or host. All nodes on a given network share the same network prefix but must have a unique host number. The addresses are represented with decimal numbers because they are easier to remember than their binary counterparts. [|Webpedia/IP addressing] Domain Names A domain name is an identification label based on the Domain Name System (DNS). A domain name can represent one or more IP addresses. Because the Internet is based on IP addresses, not domain names, every Web server requires a DNS server to translate domain names into IP addresses. Domain names are used in URLs to identify particular Web pages. The registration of these domain names is usually administered by domain name registrars who sell their services to the public. Domain names are separated into levels with the first-level called top-level domains (TLDs). Included are the prominent domains .com, .net and .org, and the country code top-level domains (ccTLDs) such as .ca, .de, and .uk. An important purpose of domain names is to provide easily recognizable and memorizable names to numerically addressed Internet resources. [|Wikipedia/Domain Names] URLs URL is the abbreviation for Uniform Resource Locator, the global address of documents and other resources on the World Wide Web. The first part of the address is called a protocol identifier and it indicates what protocol to use, and the second part is called a resource name and it specifies the IP address or the domain name where the resource is located. The protocol identifier and the resource name are separated by a colon and two forward slashes. For example, the two URLs below point to two different files at the domain pcwebopedia.com. The first specifies an executable file that should be fetched using the FTP protocol; the second specifies a Web page that should be fetched using the HTTP protocol: ftp://www.pcwebopedia.com/stuff.exe http://www.pcwebopedia.com/index.html [|Webopedia/URL] Reference Webopedia:[|Understanding IP Addressing] [|URL] Wikipedia:[|Domain Names] Previous Page: ISPs Next Page: Packet Switching