Updated: 12/05/2021 by Computer Hope Show
Also known as an internet address or web address, a URL (Uniform Resource Locator) is a URI and standardized naming convention for addressing documents accessible over the Internet and Intranet. The URL makes it possible for a computer to locate and open a web page on a different computer on the Internet. An example of a URL is https://www.computerhope.com, the URL for the Computer Hope website. Below is additional information about each section of the HTTP URL for this page.  http:// or https://The "HTTP" stands for Hypertext Transfer Protocol. It lets the browser know which protocol it's going to use to access the information specified in the domain. An "HTTPS" protocol is short for "Hypertext Transfer Protocol Secure" and indicates that information transmitted over HTTP is encrypted and secure. After the HTTP or HTTPS is the colon ( : ) and two forward slashes ( // ) separate the protocol from the remainder of the URL. Tip A URL is not explicit to HTTP or HTTPS addresses; FTP, TFTP, Telnet, and other addresses are also considered URLs and may not follow the same syntax as our example. www.Next, "www" stands for World Wide Web and is used to distinguish the content. This portion of the URL is not required and can be left out many times. For example, typing "http://computerhope.com" would still get you to the Computer Hope website. The address portion can also be substituted for an important sub-page known as a subdomain. computerhope.comNext, "computerhope.com" is the domain name for the website. The last portion of the domain is known as the domain suffix or TLD. It is used to identify the type or location of the website. For example, ".com" is short for commercial, ".org" is short for an organization, and ".co.uk" is the United Kingdom. There are several domain suffixes available. To get a domain, you would register the name through a domain registrar. /jargon/u/Next, "jargon" and "u" are the directories where the web page is on the server. In this example, the web page is two directories deep. To find the file on the server, it would be in the /public_html/jargon/u directory. The public_html directory is the default directory containing the HTML files with most servers. url.htmFinally, url.htm is the actual web page on the domain you're viewing. The trailing .htm is the file extension of the web page that indicates the file is an HTML file. Other common file extensions on the Internet include .html, .php, .asp, .cgi, .xml, .jpg, and .gif. Each of these file extensions performs a different function, like all the different types of files on your computer. Tip As you may have noticed, the protocol, domain, directories, and files are separated by forward slashes ( / ). Where is the URL located?A URL is usually located at the top of the browser window in the address bar or omnibox. On desktop computers and laptops, the URL is always visible unless your browser is being displayed in fullscreen. In most smartphone and tablet browsers, the address bar containing the URL disappears as you scroll down and only show the domain when visible. When the address bar is not visible, scroll up the page. If only the domain is shown, tapping on the address bar shows the full address. Tip Most video-sharing pages, such as YouTube, also have sharing links below the video or in the video. Using these sharing links is another way to get the URL of the video. How to open a URLYou can open a URL by clicking a hyperlink. For example, clicking "hyperlink" in this paragraph opens a page describing hyperlinks. If a URL is in printed material (e.g., e-mail or magazine) where it's not a hyperlink, you can open the page by typing the URL in the browser address bar. If the URL is in an e-mail, it can also be copied and pasted to the browser address bar. Tip Some printed material may also have a QR code to scan to open a web page with your smartphone. How can I create my own URL?Many social networking sites like Instagram, or shopping platforms like Etsy, allow you to have custom directories that link to your page. For example, the Computer Hope Facebook profile is at "facebook.com/computerhope". However, this URL is not a full URL but a specific section dedicated to your user profile. To create a fully unique URL, such as "computerhope.com", you need to obtain a custom domain from a domain name registrar. These companies allow you to purchase domain names, which can be attached to your website(s) or redirected to any web page you choose. You are usually required to renew your domain on an annual basis. Domains are priced based on their marketability and historical use. Domain suffixes like .com, .net, or .org also affect the price. Once purchased, domain names can be transferred between registrars or linked to other websites while you own the domain. Popular domain name registrars include:
Website builders like Wix, Weebly, and Squarespace also allow you to purchase custom domain names automatically tied to your custom website. What characters are not allowed in a URL?Most people realize that spaces are not allowed in a URL. However, it is also important to realize, as documented in RFC 1738, the URL string can only contain alphanumeric characters and the !$-_+*'(), characters. Any other characters that are needed in the URL must be encoded. Understanding more complex URLs and parametersWhen a URL points to a script that performs additional functions, additional information (parameters) is added to the end of the URL. For example, a search engine URL pointing to a search results page includes a parameter with the search query words. Below is an example URL that points to the Computer Hope search page, with the search query parameter of "example search". https://www.computerhope.com/cgi-bin/search.cgi?q=example%20searchIn this URL, the script file being pointed to is search.cgi in the cgi-bin directory. Because this file ends with .cgi, it is assumed to be a Perl script. After the script file name is a ? (question mark). The question mark in a URL separates the URL from all the parameters or variables sent to the script. In the example above, the parameter is q=example%20search. The "q" is a variable name, and the "example%20search" is the value for that variable. Because no spaces are allowed in a URL, the space is encoded as %20. In many scripts, a + (plus) is also used to represent a space. In our example, the script would use it as it is executed because there is a variable. Scripts are also not limited to only one variable. If the script needs multiple variables, each variable can be separated with a & (ampersand), as shown in the example below. https://www.computerhope.com/cgi-bin/search.cgi?q=example%20search&example=testIn the example above, there are two different variables. The "q" variable equals "example search", and the "example" variable equals "test". If the script looked for an example variable, it could be processed and perform an additional feature. Is an IP address the same as a URL or web address?No. An IP address is a unique number assigned to each device on a network. A domain name is assigned a unique IP address on the World Wide Web. When typed (e.g., computerhope.com), DNS translates the domain name into an IP address that routers use to find the web server. A domain name is used instead of an IP address because it's easier for humans to remember. For example, it's easier to remember "computerhope.com" than it is to remember an IP address like "216.58.216.164". See our IP address for further information about an IP. Tip You could think of a domain name like a house picture and the IP address as the house's address. The picture gives you a representation of what the house looks like, but without the address, you'd never be able to locate that house. Address, Computer acronyms, cURL, Internet, Internet terms, Intranet, IP, Naked URL, SEO terms, URI, URL Shortener, Web design terms, Whack
The internet is the world’s most popular computer network. It began as an academic research project in 1969, and became a global commercial network in the 1990s. Today it is used by more than 2 billion people around the world. The internet is notable for its decentralization. No one owns the internet or controls who can connect to it. Instead, thousands of different organizations operate their own networks and negotiate voluntary interconnection agreements. Most people access internet content using a web browser. Indeed, the web has become so popular that many people incorrectly treat the internet and the web as synonymous. But in reality, the web is just one of many internet applications. Other popular Internet applications include email and BitTorrent. Where is the internet?The internet has three basic parts:
Cables at an Internet Exchange Point. (Fabienne Serriere) Who created the internet?The internet began as ARPANET, an academic research network that was funded by the military’s Advanced Research Projects Agency (ARPA, now DARPA). The project was led by Bob Taylor, an ARPA administrator, and the network was built by the consulting firm of Bolt, Beranek and Newman. It began operations in 1969. In 1973, software engineers Vint Cerf and Bob Kahn began work on the next generation of networking standards for the ARPANET. These standards, known as TCP/IP, became the foundation of the modern internet. ARPANET switched to using TCP/IP on January 1, 1983. During the 1980s, funding for the internet shifted from the military to the National Science Foundation. The NSF funded the long-distance networks that served as the internet’s backbone from 1981 until 1994. In 1994, the Clinton Administration turned control over the internet backbone to the private sector. It has been privately operated and funded ever since. Did Al Gore invent the internet?Former Vice President Al Gore is frequently quoted as claiming credit for the invention of the internet, but what he actually said in a 1999 CNN interview was “I took the initiative in creating the internet.” Gore was widely mocked for this statement. But the men who did invent the internet, TCP/IP designers Bob Kahn and Vint Cerf, wrote in Gore’s defense in 2000. They argue that Gore was “the first political leader to recognize the importance of the internet and to promote and support its development.” “As far back as the 1970s Congressman Gore promoted the idea of high speedtelecommunications,” the pair wrote. “As a Senator in the 1980s Gore urged government agencies to consolidate what at the time were several dozen different and unconnected networks into an ‘Interagency Network.’” Gore sponsored the 1991 High Performance Computing and Communications Act, which Kahn and Cerf say “became one of the major vehicles for the spread of the internet beyond the field of computer science.“ Who runs the internet?No one runs the internet. It’s organized as a decentralized network of networks. Thousands of companies, universities, governments, and other entities operate their own networks and exchange traffic with each other based on voluntary interconnection agreements. The shared technical standards that make the internet work are managed by an organization called the Internet Engineering Task Force. The IETF is an open organization; anyone is free to attend meetings, propose new standards, and recommend changes to existing standards. No one is required to adopt standards endorsed by the IETF, but the IETF’s consensus-based decision-making process helps to ensure that its recommendations are generally adopted by the internet community. The Internet Corporation for Assigned Names and Numbers (ICANN) is sometimes described as being responsible for internet governance. As its name implies, ICANN is in charge of distributing domain names (like vox.com) and IP addresses. But ICANN doesn’t control who can connect to the internet or what kind of information can be sent over it. What’s an IP address?Internet Protocol addresses are numbers that computers use to identify each other on the internet. For example, an IP address for vox.com is 216.146.46.10. An ICANN department known as the Internet Assigned Numbers Authority is responsible for distributing IP addresses to ensure that two different organizations don’t use the same address. The current internet standard, known as IPv4, only allows for about 4 billion IP addresses. This was considered a very big number in the 1970s, but today, the supply of IPv4 addresses is nearly exhausted. So internet engineers have developed a new standard called IPv6. IPv6 allows for a mind-boggling number of unique addresses — the exact figure is 39 digits long — ensuring that the world will never again run out. At first, the transition to IPv6 was slow. Technical work on the standard was completed in the 1990s, but the internet community faced a serious chicken-and-egg problem: as long as most people were using IPv4, there was little incentive for anyone to switch to IPv6. But as IPv4 addresses became scarce, IPv6 adoption accelerated. The fraction of users who connected to Google via IPv6 grew from 1 percent at the beginning of 2013 to 6 percent in mid-2015. How does wireless internet work?In its early years, internet access was carried over physical cables. But more recently, wireless internet access has become increasingly common. There are two basic types of wireless internet access: wifi and cellular. Wifi networks are relatively simple. Anyone can purchase wifi networking equipment in order to provide internet access in a home or business. Wifi networks use unlicensed spectrum: electromagnetic frequencies that are available for anyone to use without charge. To prevent neighbors’ networks from interfering with each other, there are strict limits on the power (and therefore the range) of wifi networks. Cellular networks are more centralized. They work by breaking up the service territory into cells. In the densest areas, cells can be as small as a single city block; in rural areas a cell can be miles across. Each cell has a tower at its center providing services to devices there. When a device moves from one cell to another, the network automatically hands off the device from one tower to another, allowing the user to continue communicating without interruption. Cells are too large to use the unlicensed, low-power spectrum used by wifi networks. Instead, cellular networks use spectrum licensed for their exclusive use. Because this spectrum is scarce, it is usually awarded by auction. Wireless auctions have generated tens of billions of dollars in revenue for the US treasury since the first one was held in 1994. What is the cloud?The cloud describes an approach to computing that has become popular in the early 2000s. By storing files on servers and delivering software over the internet, cloud computing provides users with a simpler, more reliable computing experience. Cloud computing allows consumers and businesses to treat computing as a utility, leaving the technical details to technology companies. For example, in the 1990s, many people used Microsoft Office to edit documents and spreadsheets. They stored documents on their hard drives. And when a new version of Microsoft Office was released, customers had to purchase it and manually install it on their PCs. In contrast, Google Docs is a cloud office suite. When a user visits docs.google.com, she automatically gets the latest version of Google Docs. Because her files are stored on Google’s servers, they’re available from any computer. Even better, she doesn’t have to worry about losing her files in a hard drive crash. (Microsoft now has its own cloud office suite called Office 365.) There are many other examples. Gmail and Hotmail are cloud email services that have largely replaced desktop email clients such as Outlook. Dropbox is a cloud computing service that automatically synchronizes data between devices, saving people from having to carry files around on floppy disks. Apple’s iCloud automatically copies users’ music and other files from their desktop computer to their mobile devices, saving users the hassle of synchronizing via a USB connection. Cloud computing is having a big impact for businesses too. In the 1990s, companies wanting to create a website needed to purchase and operate their own servers. But in 2006, Amazon.com launched Amazon Web Services, which allows customers to rent servers by the hour. That has lowered the barrier to entry for creating websites and made it much easier for sites to quickly expand capacity as they grow more popular. What is a packet?A packet is the basic unit of information transmitted over the internet. Splitting information up into small, digestible pieces allows the network’s capacity to be used more efficiently. A packet has two parts. The header contains information that helps the packet get to its destination, including the length of the packet, its source and destination, and a checksum value that helps the recipient detect if a packet was damaged in transit. After the header comes the actual data. A packet can contain up to 64 kilobytes of data, which is roughly 20 pages of plain text. If internet routers experience congestion or other technical problems, they are allowed to deal with it by simply discarding packets. It’s the sending computer’s responsibility to detect that a packet didn’t reach its destination and send another copy. This approach might seem counterintuitive, but it simplifies the internet’s core infrastructure, leading to higher performance at lower cost. What is the World Wide Web?The World Wide Web is a popular way to publish information on the internet. The web was created by Timothy Berners-Lee, a computer programmer at the European scientific research organization CERN, in 1991. It offered a more powerful and user-friendly interface than other internet applications. The web supported hyperlinks, allowing users to browse from one document to another with a single click. Over time, the web became increasingly sophisticated, supporting images, audio, video, and interactive content. In the mid-1990s, companies such as Yahoo and Amazon.com began building profitable businesses based on the web. In the 2000s, full-featured web-based applications such as Yahoo Maps and Google Docs were created. In 1994, Berners-Lee created the World Wide Web Consortium (W3C) to be the web’s official standards organization. He is still the W3C’s director and continues to oversee the development of web standards. However, the web is an open platform, and the W3C can’t compel anyone to adopt its recommendations. In practice, the organizations with the most influence over the web are Microsoft, Google, Apple, and Mozilla, the companies that produce the leading web browsers. Any technologies adopted by these four become de facto web standards. The web has become so popular that many people now regard it as synonymous with the internet itself. But technically, the web is just one of many internet applications. Other applications include email and BitTorrent. What’s a web browser?A web browser is a computer program that allows users to download and view websites. Web browsers are available for desktop computers, tablets, and mobile phones. The first widely used browser was Mosaic, created by researchers at the University of Illinois. The Mosaic team moved to California to found Netscape, which built the first commercially successful web browser in 1994. Netscape’s popularity was soon eclipsed by Microsoft’s Internet Explorer, but an open source version of Netscape’s browser became the modern Firefox browser. Apple released its Safari browser in 2003, and Google released a browser called Chrome in 2008. By 2015, Chrome had grown to be the most popular web browser with a market share around 50 percent. Internet Explorer, Firefox, and Safari also had significant market share. What is SSL?SSL, short for Secure Sockets Layer, is a family of encryption technologies that allows web users to protect the privacy of information they transmit over the internet. When you visit a secure website such as Gmail.com, you'll see a lock next to the URL, indicating that your communications with the site are encrypted. Here's what that looks like in Google's Chrome browser: That lock is supposed to signal that third parties won't be able to read any information you send or receive. Under the hood, SSL accomplishes that by transforming your data into a coded message that only the recipient knows how to decipher. If a malicious party is listening to the conversation, it will only see a seemingly random string of characters, not the contents of your emails, Facebook posts, credit card numbers, or other private information. SSL was introduced by Netscape in 1994. In its early years, it was only used on a few types of websites, such as online banking sites. By the early 2010s, Google, Yahoo, and Facebook all used SSL encryption for their websites and online services. More recently, there has been a movement toward making the use of SSL universal. In 2015, Mozilla announced that future versions of the Firefox browser would treat the lack of SSL encryption as a security flaw, as a way to encourage all websites to upgrade. Google is considering taking the same step with Chrome. What is the Domain Name System?The Domain Name System (DNS) is the reason you can access Vox by typing vox.com into your browser rather than a hard-to-remember numeric address such as 216.146.46.10. The system is hierarchical. For example, the .com domain is administered by a company called Verisign. Verisign assigns sub-domains like google.com and vox.com. Owners of these second-level domains, in turn, can create sub-domains such as mail.google.com and maps.google.com. Because popular websites use domain names to identify themselves to the public, the security of DNS has become an increasing concern. Criminals and government spies alike have sought to compromise DNS in order to impersonate popular websites such as facebook.com and gmail.com and intercept their private communications. A standard called DNSSEC seeks to beef up DNS security with encryption, but few people have adopted it. Who decides what domain names exist and who gets them?The domain name system is administered by the Internet Corporation for Assigned Names and Numbers (ICANN), a non-profit organization based in California. ICANN was founded in 1998. It was granted authority over DNS by the US Commerce Department, though it has increasingly asserted its independence from the US government. There are two types of domain names. The first is generic top-level domains (gTLDs) such as .com, .edu, .org, and .gov. Because the internet originated in the United States, these domains tend to be most popular there. Authority over these domains is usually delegated to private organizations. There are also country-code top-level domains (ccTLDs). Each country in the world has its own 2-letter code. For example, the ccTLD for the United States is .us, Great Britain’s is .uk, and China’s is .cn. These domains are administered by authorities in each country. Some ccTLDs, such as .tv (for the island nation of Tuvalu) and .io (the British Indian Ocean Territory), have become popular for use outside of their home countries. In 2011, ICANN voted to make it easier to create new gTLDs. As a result, there may be dozens or even hundreds of new domains in the next few years.
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Popular sites like google and yahoo! have several computers assigned to their host names because:
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