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What is a Domain Name? A domain name is the address of a website on the Internet. Yahoo's address is yahoo.com, Microsoft's address is microsoft.com, Fry's Electronics address is outpost.com and so on. A domain name is a unique name that has been registered for use in the Internet's Domain Name System which is like an electronic phone directory for looking up domain names. Domain names always have two parts to them, separated by dots, like this: myname.com yahoo.com. learn.net w3.org The first part of the domain name is called the top level domain. In myname.com, "com" is the top level domain. The second part is a unique name belonging to a top level domain. In myname.com, "myname" is a unique name in the "com" top level domain. The two parts taken together make up the domain name. Name Domain | | myname.com To help understand how the names relate, you could read the dot between the two parts as the word "in"- myname.com could be read as follows: Name in Domain | | | myname . com The rule is that every name in a particular top level domain must be unique. Since there are many top level domains in which a name could be used to form a domain name, the names themselves are not unique. Only the two-part domain name itself can be and must be unique. As an example, the name "myname" could be part of all of the following domain names: myname.com myname.net myname.org myname.de As you can see, each one of the above domain names is unique but the name itself "myname" isn't unique. Top Level Domains Specific top level domains have been authorized for use in the official Internet domain name system. The domains that are currently authorized are 2 to 4 characters in length. There are two broad categories of top level domains - generic and country. Generic domains are reserved for use for a particular type of activity on the Internet. Examples of the generic domains include .com, .org, and .net. They are often referred to as generic top-level domains or "gTLD"s. .com is for commercial or business use .net is for network use .org is for non-profit, non-commerical use The following generic domains are special top-level domains and are often referred to as "sTLDs". .edu is for 4-year colleges .gov is for U.S. federal government agencies .mil is for U.S. military organizations .int is for International treaty organizations Each country or territory in the world has its own country domain. These are often referred to as country codes or "cc"s. The United Kingdom, for example, uses .uk. France uses .fr, Denmark .dk, and so on. Click here for a full list of country domains. Some countries will preface their country codes with a generic domain such as .com.uk. What is a Canonical Domain Name? When you own a domain name such as myname.com, you can create canonical domain names with it. This is done by adding a name before your domain name, followed by a dot. As an example, if you own the domain name myname.com, you could create the following canonical domain names: info.myname.com contact.myname.com about.myname.com email.myname.com You do not have to register canonical domain names. You only have to register the domain name you are building a canonical name from. There is no restriction on how many canonical names you can create with your domain name. Canonical names are usually referred to as sub-domains. What is a URL? URL stands for Uniform Resource Locator. A URL maps out the address, exact location, file name and type of resource you are requesting from a website so your computer system can find and display it correctly. Here's an example of a typical URL: http://www.darinswan.com/dchains/resourcesites.htm A URL is organized in parts, separated by specific symbols such as right slashes, dots or colons, in a very specific order. If you get the order wrong or put in the wrong separators, or make a typing error on the name of any of the parts, your computer system may not be able to locate the resource you want. Part 1: Transfer Protocol When you get your driver's license, you learn the system of rules and procedures for driving on the roads and freeways. The Internet has a similar set of rules and procedures for moving information around. On the Internet, the rules are called protocols. The transfer protocol tells your computer system what type of information is going to be located and transferred to your computer. It is always a word or abbreviation followed by a colon and two right-slashes. Here are the most common types:
Part 2: Host Name The host name gives the address to the computer that is hosting or storing the files you want to find. It is organized in two sections and each part of the host name is separated by dots. The host name is followed by a right-slash to show that that's the end of the host name. In the following example, the host name is in red text: http://www.domains.sharlee.com/dchains/resourcesites.htm The first section of the host name is the abbreviation for the network service that is running on the hosting computer. There are many different types of network services that a hosting computer can run. The most common is www, which stands for World Wide Web - a network service that makes files and information available to users on the World Wide Web. Note: If you type in a URL starting with "http://", you don't always have to type in the network service abbreviation "www". This is because many computer systems will automatically insert it for you. In the following example the network service prefix is in red text: http://www.domains.sharlee.com/dchains/resourcesites.htm ftp://ftp.domains.sharlee.com/dchains/resourcesites.pdf The second section of the host name is the domain nameor a sub-domain name for the hosting computer. The domain name is in red text: http://www.sharlee.com/dchains/resourcesites.htm A sub-domain on the same domain name is in red text: http://domains.sharlee.com/dchains/resourcesites.htm Note: You do not add www before a sub-domain. Part 3: Directory/Subdirectory Part 3 of the URL tells the computer system which directory and/or subdirectory (path) to look in to find the resource you want. The directory and subdirectory names are separated and ended by the right slash character. In this example, the full path isn't shown. The computer system will automatically show the index page in the directory named dchains: http://www.domains.sharlee.com/dchains/ In this example, the directory "dchains" is in red text: http://www.domains.sharlee.com/dchains/doc1.htm In this example, the directory "dchains" and the subdirectory "resourcesites" are in red text: http://www.domains.sharlee.com/dchains/resourcesites/doc1.htm Part 4: File Name Part 4 of the URL shows the file or document's name, followed by a dot, followed by the standard abbreviation for the file type extension. In this example, the file name is shown in red text: http://www.domains.sharlee.com/dchains/resourcesites.htm Files that are web pages usually end in .htm or .html. There are many other extensions that are used on the web for file types like graphic images, compressed files and so on. For some types of files, the file extension isn't necessary. Part 5: Parameters If you use a search engine or click on some links on a website, you will see part 5 of the URL. This is a series of characters that tell the computer system where to look within a file to get the exact information you are looking for. In the following examples, the parameters are in red text: http://www.altavista.com/cgi-bin/query?pg=q &q=directory:bus&stq=10 http://www.instantweb.com/foldoc/foldoc.cgi?hostname The parameter section begins with a symbol like ? or # and provides the necessary search information in the characters that follow. What is an IP Address? Each computer connected to the Internet has a unique numeric address assigned to it. This number is called the Internet Protocol (IP) address. You could think of this address as the computer's telephone number on the Internet. The IP address is made up of four numbers that are separated by dots, like this: 216.32.74.50 or like this: 209.15.63.7. Each of the four numbers can be 1 to 3 digits long. Internet Service Providers (ISPs) buy blocks of IP addresses, which they assign to their customers. Each time you go online, your ISP assigns you an IP address from their block of IP addresses. When you set up a website with your ISP, your ISP sets up disk space for you on their computer system. This is your webspace location on their system. Then they assign your location a specific IP address from their block of IP addresses. Most ISPs assign the same IP address to many websites. These are called virtual IPs. If you have your own IP address which you do not share with any other website you have what is called a static IP address. If a website has a static IP address, you can type the website's IP address in your browser address bar instead of the website's name. As an example, you can get to Yahoo's website by typing yahoo.com or by typing 66.94.234.13. Either one will take you to Yahoo's website. If you know the IP address of a website, you can look up the domain name using a lookup tool: Click Here and enter Yahoo's IP Number: 66.94.234.13 What is the Domain Name System? The DNS or Domain Name System is simply a system that matches domain names with IP addresses. This makes life a lot easier for people. Remembering and typing a domain name is much easier than remembering and typing the 4 to 12 numbers of an IP address. As an example, when you type yahoo.com in your browser, the domain name system fetches Yahoo's IP address, which is 216.32.74.50 and connects you to the Yahoo website. An IP address can have more than one domain name matched to it. As an example, the IP address 66.94.234.13 could have both yahoos.com and yahoo.com matched up to it. |
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