Glossary

The measure of how accessible a website is. An accessible website provides features that allow the site to be used more easily by users with disabilities.

Asynchronous JavaScript And XML, is a Web development technique for creating interactive web applications. The intent is to make web pages feel more responsive by exchanging small amounts of data with the server behind the scenes, so that the entire Web page does not have to be reloaded each time the user makes a change. This is meant to increase the Web page’s interactivity, speed, and usability.

Text which is displayed when moving a mouse to hover over an image. Alternate text is also displayed in place of an image if the visitor has image viewing turned off in their browser. Alternate text can also help with SEO.

A service offered by domain registrars which allows registration of a domain without making the personal details of the owner publicly available.

Allows guests to upload files to the account. Files are upload to a separate directory so that the website files can not be altered by guests. Requires dedicated IP address.

The software that is used on the servers to serve webpages.

A small application, such as a utility program or limited-function spreadsheet or word processor. Java programs that are run from the browser are always known as applets.

American Standard Code for Information Interchange. Pronounced “ask-ee,” it is the built-in binary code for representing characters in all computers except IBM mainframes, which use the EBCDIC coding system. ASCII was originally developed for communications and uses only seven bits per character, providing 128 combinations that include upper and lower case alphabetic letters, the numeric digits and special symbols such as the $ and %. The first 32 characters are set aside for communications and printer control.

A file that is attached to an email message.

The verification of a user that is logging into a server, such as logging into the Control Panel. Authentication requires a username and password.

The major network connections that make up the internet.

A saved copy of the files for your website. It can be used to restore your site if anything happens to the original files.

A measure of the amount of data that can be transferred over a network in a specific amount of time.

An image containing an advertisement which is displayed on a website.

A method of transferring binary files with an FTP client.

Shortened form of ‘weblog’. A website containing a series of dated entries, generally on a specific topic, which are written by an individual.

The section of an HTML document that contains the content.

High-speed internet access.

Short for Web Browser, a software application used to locate and display Web pages. The two most popular browsers are Netscape Navigator and Microsoft Internet Explorer. Both of these are graphical browsers, which means that they can display graphics as well as text. In addition, most modern browsers can present multimedia information, including sound and video, though they require plug-ins for some formats.

A comment is a component of a programming language that allows the programmer to tell the parser to ignore anything within the comment. The method for indicating a comment varies from language to language.

Content Management System. A software package that enables content to be managed on one or more websites. A content management system allows one or more authors to prepare and publish information online, without needing to prepare HTML code. Modern systems allow information and resources (images, scripts, etc.) to be stored in a database for re-use, automatic indexing and searching, and for workflow management (authorisation, publication, retirement, archiving).

CSS or Cascading Style Sheets: Groups of rules or properties called style sheets, which may be used to define the fonts, colors and layouts of a web site. This is one way of defining the format of a web site.

Davatar which means Dynamic Avatar, pronounce as “Daa-va-tar”. You can get a free Davatar at http://www.davatar.net.

Dynamic Avatar greatly enhances the traditional avatar, not only allowing rich information presentation on the same piece of image, but also provide a centralized identity managment system. It uses the technology of dynamically generating images on fly to give viewers different experience on each request.

Access to the Internet achieved using a computer modem and standard telephone line.

The name of a web site. It follows the “www.” part of a web site address (e.g.. www.macropages.com) and the “@” in an email address (e.g.. info@macropages.com). A domain name should be easy to remember and have some meaning relating to a site.

Denial of Service Attack. An attack against a computer or network that attempts to limit or prevent access to the Internet by flooding it with requests (for a webpage or online resource) or email (causing the email system to overload). A more sophisticated variant of this attack is a distributed denial of service attack, which uses multiple computers for this purpose, increasing the amount of traffic and reducing defences of the victim’s machine or network.

The common term for “electronic mail”, a method for writing, sending and receiving electronic text (and audio and/or video) over a computer network. A variation of email popular with mobile telephone users is the Short Messaging Service (SMS). Email differs to other messaging systems in that it is asynchronous in nature (see Instant Messaging).

Animation software designed by Macromedia Corp. Flash elements can include simple text or button animations, scrolling text, slide show pictures and even flash movies, complete with sound. Flash is not appropriate for all web sites as it can only be viewed in a linear fashion and therefore may restrict a visitor’s interactivity with the web site. Also, many flash elements take time to load and require a special plug in to be installed on a user’s computer before they can be viewed.

In a URL, a single part of the path to a page. A folder is a named storage area on the computer containing files and other folders. In http://my.web.site/sample/test.htm, sample/ is a folder. Folder also known as Directory.

A font is a complete set of characters including letters, numbers and all special symbols in a particular type and style. The type or “typeface” is named according to the design such as Arial, or Times New Roman or Courier. The style can either be plain, italic or bold.

File Transfer Protocol. A method for sending files from one computer to another on networks and the Internet. Needed to upload/download files to and from your host

Graphic interchange file, a graphics format that can be displayed in web browsers. They display in 256 colors and have built-in compression. GIF files are also used for animated web graphics.

computer memory or disk space which consists of about one thousand million bytes, one thousand megabytes. The actual value is 1,073,741,824 bytes 1,024 megabytes.

A guestbook is a script on a web page with a form that allows visitors of a website to sign and leave comments. It can be found in multiple web based programming languages, Perl, PHP, etc.

Is a slang term, and can have multiple meanings. The popular meanings include To alter a computer program or gain unauthorized entry into a program, computer, or computer system.

An HTML tag that defines the head of the document, it contains the <title> tag (document title), and can contain scripts, and other page attributes.

represent the total number of requests made to the server during a given time period

The central document on a web site. The document usually directs visitors to the information that can be found within the site. Also can be a personal page for a person, which contains information about him or her.

Also called a link, a hyperlink is an electronic connection between a web page and another web page on the same site, or another web page on an entirely different site. Hyperlinks can be text, image or graphic links (such as buttons) and are activated by clicking on them with a mouse.

A computer program that allows near-instantaneous (synchronous) communication between computer users. This communication can take a variety of forms, from text (similar to an email) to videoconferencing. A variant of this type of application for mobile telephones is the SMS.

A type of property that is protected by copyright or patent laws. Intellectual property is the product of intellectual processes, such as scholarship or creative work.

A world-wide network of computer systems and networks that share information and data using a standard communication protocol (Internet Protocol).

“Internet Protocol”. The basic addressing protocol of the Internet which allows resources to be located across the distributed network.

Internet Service Provider. A company which provides access to the internet through a regular or high speed Dial-up (phone line) Connection or via Satellite. An ISP can be a small local provider or a large national provider such as MSN, Earth Link and AOL. Often times they also provide you with an email address as well.

JavaScript is a script language - a system of programming codes, created by Netscape, that can be embedded into the HTML of a web page to add functionality. JavaScript should not be confused with the Java programming language.

Joint Photographic Experts Group. JPEG is a standards committee that designed an image compression format. The compression format they designed is known as a lossy compression, in that it deletes information from an image that it considers unnecessary. JPEG files can range from small amounts of lossless compression to large amounts of lossy compression. This is a common standard on the WWW, but the data loss generated in its compression make it undesirable for printing purposes.

The word or phrase that is used in a search engine to find websites related to a particular topic.

A unit used for computer storage that is equal to 1024 bytes.

The acronym LAMP refers to a set of free software programs commonly used together to run dynamic Web sites or servers:

• Linux, the operating system
• Apache, the Web server
• MySQL, the database management system (or database server)
• PHP, Perl, and/or Python, the scripting languages.

An open source operating system that is often used for web servers.

Distribution of tasks between multiple servers in order to more effectively handle resource-intensive websites.

A discussion group, generally about a specific topic, where readers post and read messages via email.

An HTML tag, which is not part of the HTML specification, that creates scrolling text.

A hashing algorithm that is used to convert a message into a unique string of digits.

A method of transmitting media, such as audio and video clips, across the internet without requiring the entire file to download before the file can be played. The file is played as it arrives on the user’s computer.

A unit of computer storage equal to 1024 kilobytes or 1,048,576 bytes.

A service provided by a financial institution that allows a website to process credit card orders.

An application for the web that allows users to post and read messages about a particular topic.

An HTML tag placed in the head section of an HTML document that allows the author to give information about the document. The most common uses are specifying a description and keywords for a document.

Multipurpose Internet Mail Extensions.

Identifies the format of a file.

An exact duplicate of a website. A mirror is commonly used to make file downloads more reliable by giving multiple locations from which users can download.

The organization that produces the Mozilla suite of applications as well as Firefox (a browser) and Thunderbird (an email client).

Information presented in a variety of formats that can include textual, audio and video.

A free, open source database that is commonly used to run dynamic websites.

A computer (server) that has both the software and the data (zone files) needed to resolve domain names to Internet Protocol (IP) numbers. Domain names must be programmed into a minimum of two name servers hosted on separate networks.

A widely known company that developed the Netscape Navigater web browser, for viewing web pages.

Refers to a program in which the source code is available to the general public for use and/or modification from its original design free of charge.

Another popular web browser. http://www.opera.com/

The state of being an owner. In web-hosting terms, this usually refers to the permissions set for directories and files for your website.

In networking, a packet is a unit of information transmitted as a discrete entity from one node on the network to another. More specifically, in packet-switching networks, a packet is a transmission unit of a fixed maximum length that contains a header, a set of data, and error control information.

Google’s patent pending technology that rates the “importance” of a given web page. Page Rank is used by Google (among other things) to determine a page’s rank on Google’s query results page.

A means of controlling access to web pages/sites.

“Portable Document Format”; a computer file format originally developed by Adobe Systems which allows for the capture of formatting information that preserves the intended layout and design of the original author.

A set of permissions associated with every file and directory that determine who can read it, write to it, or execute it. Only the owner of the file (or the super-user) can change these permissions.

Refers to a collection of photos displayed on a web site.

Individual tiny dots of light which display colors, images and text on a screen. Most images and font sizes used in websites are measured in pixels.

Portable Network Graphics (PNG) format was designed to be a patent-free successor to the GIF format. PNG offers particular benefits in this environment such as improved image compression ( 10 to 30 percent smaller than GIFs), two dimensional interlacing, storage of text with the an image making it possible for search engines to gather information and offer subject searching for images in a standard way.

A referrer is the URL of the page from which a user accesses another page. For example, if you have two pages,example.com/page1.html and example.com/page2.html, and someone accesses example.com/page2.html from a link on example.com/page1.html, the referrer would be example.com/page1.html. The referrer URL is sent by most browsers as part of a request for a page. If a user makes a direct request for a page (for example, typing example.com/page2.html into the address bar), there will be no referrer information sent.

A registrar is a company that handles domain name registrations. They sell domains and allow their customers to manage domains they have purchased.

A network device that forwards packets from one network to another. Based on internal routing tables, routers read each incoming packet and decide how to forward it. To which interface on the router outgoing packets are sent may be determined by any combination of source and destination address as well as current traffic conditions (load, line costs, bad lines, etc.).

Really Simple Syndication. A syndication format that was developed by Netscape in 1999 and became very popular for aggregating updates to blogs and the latest news from Web sites. RSS has also stood for “Rich Site Summary” and “RDF Site Summary.”

The default Web browser for the Max OS X operating system. It is noted for its fast download speed and many built-in features including the Google search bar and popup blocker

How much a system can be expanded.

Software for the visually impaired that reads the contents of a computer screen, converting the text to speech. Screen readers are designed for specific operating systems and generally work with most applications.

A program written in a general-purpose programming language. Such languages are typically interpreted and less comprehensive than full-blown compiled languages.

Software that searches for data based on some criteria. Although search engines have been around for decades, they were brought to the forefront after the Web exploded onto the scene. Every Web search engine site uses a search engine that it has either developed itself or has purchased from a third party. Search engines can differ dramatically in the way they find and index the material on the Web, and the way they search the indexes from the user’s query.

The protection of data, networks and computing power. The protection of data (information security) is the most important. The protection of networks is important to prevent loss of server resources as well as to protect the network from being used for illegal purposes. The protection of computing power is relevant only to expensive machines such as large supercomputers.

Search Engine Optimization. Designing a Web site so that search engines easily find the pages and index them. The goal is to have your page be in the top 10 results of a search. Optimization includes the choice of words used in the text paragraphs and the placement of those words on the page, both visible and hidden inside meta tags. Search engines use different criteria for indexing, and those criteria may change. Thus, it becomes increasingly difficult to satisfy every one equally. Yahoo! and other directory-oriented search sites manually index a Web site, which may provide the best results for the user.

A computer system in a network that is shared by multiple users. Servers come in all sizes from x86-based PCs to IBM mainframes. A server may have a keyboard, monitor and mouse directly attached, or one keyboard, monitor and mouse may connect to any number of servers via a KVM switch. Servers may be also be accessed only through a network connection as well.

A method for maintaining state throughout a website. It is most often used to keep users logged in so that they can access features on a site.

A hosting solution where multiple user’s sites are hosted on the same server.

A browser plugin created by Macromedia that allows playback of multimedia files.

Software on a website that allows customers to save items they wish to purchase and checkout when they have finished shopping.

Short Message Service. A service that permits the exchange of text messages via mobile phones.

Simple Object Access Protocol. A protocol based on XML that is frequently used in web services.

Unsolicited bulk email. Unsolicited means that the Recipient has not granted verifiable permission for the message to be sent. Bulk messages are messages that are sent massively and contain identical content.

A program that surfs webpages to get the links and pass the caught links to another program to be processed. It is usually used by search engines.

Email address spoofing is an activity of illegally using other’s legitimate email address to send messages.

A program that is installed without user’s consent and running secretly on computer to collect user’s information and pass it to other parties. Spyware is installed as a result clicking on unreliable popup windows or drive-by download (automatic download without user’s consent and knowledge).

Server Side Includes are directives that are placed in HTML pages, and evaluated on the server while the pages are being served. They let you add dynamically generated content to an existing HTML page, without having to serve the entire page via a CGI program, or other dynamic technology. SSI page can be identified by .shtml file extension.

Secure Sockets Layer is a protocol developed by Netscape for transmitting private documents via the Internet.

Space in hard disk to store data such as webpages, databases and configuration files. Each user account is assigned a storage quota on the server.

To transmit data over a network. Video and Audio streaming mean to upload, download or play Video and Audio file.

Sub domain is a domain that is part of a larger domain. In domain name test.domain.com, “test” is the sub domain.

SVG (Scalable Vector Graphics) is a language that delivers two-dimensional graphics in XML to the web. It provides dynamic and reusable vector graphic, text, and images.

A set of data elements that has a horizontal dimension (rows) and a vertical dimension (columns) in a relational database system. A table has a specified number of columns but can have any number of rows. A table is often called a relation. Rows stored in a table are structurally equivalent to records from flat files in that they must not contain repeating fields. In webpage’s it can be as simple as a spreadsheet of rows and columns, or as complex as a set of data within a database.

Transmission Control Protocol. One of the main protocols in TCP /IP networks. Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent.

A terminal emulation program for TCP /IP networks such as the Internet. The Telnet program runs on your computer and connects your PC to a server on the network. You can then enter commands through the Telnet program and they will be executed as if you were entering them directly on the server console. This enables you to control the server and communicate with other servers on the network. To start a Telnet session, you must log in to a server by entering a valid username and password. Telnet is a common way to remotely control Web servers.

A set of pre-designed formats for text and graphics on which new pages and webs can be based. After a page or web is created using a template, you can customize the page or web.

A remote email client made by Mozilla.

The title bar - the very top of the browser - displays the title of the page. The title of a web page is also displayed in search engine result pages; in minimized window titles at the bottom of the screen; and in lists of bookmarks or favorites.

The amount of activity over a communication system during a given period of time; “heavy traffic overloaded the trunk lines”; “traffic on the internet is lightest during the night”

Trojan horse. An apparently useful and innocent program containing additional hidden code which allows the unauthorized collection, exploitation, falsification, or destruction of data. Most commonly associated with viruses.

Transferring a file or files from the user’s computer to a remote computer.

Strangely enough, the opposite of downtime. It is defined as being the time that an item of equipment is in service and operating.

Uniform Resource Identifier - URIs have been known by many names: WWW addresses, Universal Document Identifiers, Universal Resource Identifiers, and finally the combination of Uniform Resource Locators (URL) and Names (URN). As far as HTTP is concerned, Uniform Resource Identifiers are simply formatted strings that identify - via name, location, or any other characteristic - a resource.

Uniform Resource Locator; an address that specifies the location of a file on the Internet (eg, http://www.fsu.edu/library). Usability - Usability is the measure of how easy it is to use a website. A site would be considered usable if it meets certain criteria, which can include: having logical navigation, adherence to established conventions for the web, and providing an easy to use help section. Many other factors can come into play.

UTF-8 (8-bit Unicode Transformation Format) is a lossless, variable-length character encoding for Unicode created by Ken Thompson and Rob Pike. It uses groups of bytes to represent the Unicode standard for the alphabets of many of the world’s languages. UTF-8 is especially useful for transmission over 8-bit Electronic Mail systems.

An automated tool to check that coding used to create web pages is valid. It is important that coding is valid as this can impact on the accessibility of pages. Assistive technology used by disabled users such as screen readers may have problems if coding is invalid. Search engines may also have difficulty indexing pages. Most web editing packages include HTML validators or checkers, alongside spell checkers. Online validators are also available, eg W3C HTML validator and Style Sheet Validator.

a complete session of accesses to a certain web server conducted by one person. A visit is concluded when the customer hasn’t viewed any page for a certain period of time (60 seconds in most cases).

World Wide Web Consortium, an international consortium of companies involved with the Internet and the Web. The W3C was founded in 1994 by Tim Berners-Lee, the original architect of the World Wide Web. The organization’s purpose is to develop open standards so that the Web evolves in a single direction rather than being splintered among competing factions. The W3C is the chief standards body for HTTP and HTML.

Web Accessibility Initiative. Guidelines put in place to highlight and improve the difficulties experienced by many web users. The guidelines can be accessed at http://www.w3.org/TR/WAI-WEBCONTENT/

Wireless Application Protocol. An open, global specification that empowers mobile users with wireless devices to easily access and interact with information and services instantly.

The server where your web site’s html files, graphics, etc. reside. Lunarpages is a web hosting company. Our servers host customer’s web sites and files.

Web services are simple, self contained applications which perform functions, from simple requests to complicated business processes. The “web services” model uses WSDL, UDDI and SOAP /XMLP. A WSDL description is retrieved from the UDDI directory. WSDL descriptions allow the software systems of one business to extend to use those of the other directly. The services are invoked over the World Wide Web using the SOAP /XMLP protocol. Each of the components are XML based. Where two agencies know about each other’s web services they can link their SOAP /XMLP interfaces - provided all security concerns are managed appropriately. It is only where services are going to have unknown users that they need to be formally described by a language such as WSDL and entered into a directory such as UDDI.

structured forms that send pre-formatted instant messages to users or a process on a server. They are designed to interact with databases to collect, store, organize and disseminate information, creating powerful tools for use in consistent information management. webApps provide (a) support of IE compatible languages (JavaScript, Flash and ActiveX, etc.), (b) synchronized Intranet, Extranet and Internet web applications, © secure unified login and presence management across all system layers, and (d) compatible with most popular database engines (SQL, Access, Sybase, etc.)

An amount of data storage space used to host websites and files on the Internet, usually measured in Megabytes (MB).

Whois is a term referring to a domain name search or look-up feature for a database - typically for Top-Level Domain name registries. Information such as name availability can be found through a query or search using a whois protocol (standard). Most Top-Level Domain registries maintain their own whois database containing domain name contact information.

A website or similar online resource which allows users to add and edit content collectively.

A media format developed by Microsoft for streaming and playing back media files.

What You See Is What You Get. A graphical interface to a process which shows how the end-result will look as it is being produced, eg a WYSIWYG HTML editor generates HTML markup but displays the document as if viewed with a Web browser.

XForms is an XML format for the specification of user interfaces, specifically web forms. XForms was designed to be the next generation of HTML / XHTML forms, but is generic enough that it can also be used in a standalone manner to describe any user interface, and even perform simple and common data manipulation tasks.

The next generation of HTML and is a hybrid between HTML and XML. XML was designed to describe data. HTML was designed to display data. XHTML is much stricter than HTML. Not all browers support XML so XHTML provides an intermediary soluton and can be interpreted by XML and HTML browsers. For further information see: http://www.w3c.org/MarkUp/

Extensible Markup Language, a specification developed by the W3C. XML is a pared-down version of SGML, designed especially for Web documents. It allows designers to create their own customized tags, enabling the definition, transmission, validation, and interpretation of data between applications and between organizations.

eXtensible Stylesheet Language Transformations. A language used to transform XML documents into other documents. In Second Site, XSLT is used to transform XML documents into HTML tags. The XSLT standard is administered by the World Wide Web Consortium (W3C).

To zip a file is to compress it into an archive so that it occupies less disk space.

Is a browser code that signals that the website page was opened successfully.

Is a browser code that signals a directory was requested instead of a file. The server substituted an index.htm file

Is a browser code that signals a temporary redirection to another page/location.

Is a browser code that means the browser understands what to do, but can’t do it for some reason.

Is a browser code that means the requested web address cannot be found.

Is a browser code that means there was an error in displaying a webpage.

Is a browser code that signals ASP is not enabled for the domain name.

Is a browser code that means there is likely an error with the coding of a ASP page.

The Apache Web server allows site managers to override the standard error page that is served for specific errors by number. This error, 400 bad request, means that a request for a URL has been made but the server is not configured or capable of responding to it. This might be the case for URLs that are handed-off to a servlet engine where no default document or servlet is configured, or the HTTP request method is not implemented.

Unauthorized. Your IP address or the username/password you entered were not correct. Your request was denied as you have no permission to access the data.

Payment Required. The data is not accessible at the time. The owner of the space has not yet payed their service provider.

Method Not Allowed. Your IP address or the username/password you entered were not correct. Your request was denied as you have no permission to access the data.

OR The server was unable to serve the data that was requested.

Not Acceptable. The document that has been requested either no longer exists, or has never existed on the server.

Proxy Authentication Required. The browser has not been authenticated on the required proxy server to access the data. This error is probably most commonly returned by content filters/parental controls.

Request Timeout. The browser has not been authenticated on the required proxy server to access the data. This error is probably most commonly returned by content filters/parental controls.

Conflict. Too many requests for the same file at one time.

OR

There is a conflict with an established software rule. (ie: you are trying to copy over a file with an older version, or you do not have permissions to delete a file)

OR

This could be caused by a DNS issue.

Gone. This is like a 404 error in that the document requested is not on the server, however this differs in that the server ‘knows’ that the file used to be there and ‘believes’ that the file may be back, so it returns 410 rather 404.

Length Required. Your Web server thinks that the HTTP data stream sent by the client (e.g. your Web browser or our CheckUpDown robot) should include a ‘Content-Length’ specification. This is typically used only for HTTP methods that result in the placement of data on the Web server, not the retrieval of data from it.

Precondition Failed. Your Web server thinks that the HTTP data stream sent by the client (e.g. your Web browser or our CheckUpDown robot) included a ‘Precondition’ specification which the server detected was not met.

Request Entity Too Large. Your Web server thinks that the HTTP data stream sent by the client (e.g. your Web browser or our CheckUpDown robot) was simply too large i.e. too many bytes. What constitutes ‘too many bytes’ depends partly upon the operation being attempted. For example a request to upload a very large file (via the HTTP PUT method) may encounter a ceiling on upload file size set by the Web server.

Request URI Too Long. Your Web server thinks that the HTTP data stream sent by the client (e.g. your Web browser or our CheckUpDown robot) contains a URL that is simply too large i.e. too many bytes.

Typically Web servers set fairly generous limits on length for genuine URLs e.g. up to 2048 or 4096 characters. If your URL is particularly long, you can usually try shorter variations to see roughly where the limit is. If your long URL is indeed valid, then the Web server may need to be reconfigured to allow your URLs through. Understand that Web servers have to set some reasonable limit here, because they have to deal with badly programmed clients trying to give them huge garbage URLs.

Unsupported Media Type. Your Web server thinks that the HTTP data stream sent by the client (e.g. your Web browser or our CheckUpDown robot) identifies a URL resource whose actual media type 1) does not

agree with the media type specified on the request or 2) is incompatible with the current data for the resource or 3) is incompatible with the HTTP method specified on the request.Detecting exactly what is causing this problem can be difficult, because there a number of possible reasons. Often the request involves transfer of data from the client to the Web server (e.g. a file upload via the PUT method), in which case you need to confirm with your ISP which media types are acceptable for upload.

Not implemented. Your Web server does not understand or does not support the HTTP method it finds in the HTTP data stream sent to it by the client (e.g. a Web browser or our CheckUpDown robot).

Bad Gateway. A server (not necessarily a Web server) is acting as a gateway or proxy to fulfill the request by the client (e.g. your Web browser or our CheckUpDown robot) to access the requested URL. This server received an invalid response from an upstream server it accessed to fulfill the request.This usually does not mean that the upstream server is down (no response to the gateway/proxy), but rather that the upstream server and the gateway/proxy do not agree on the protocol for exchanging data. Given that Internet protocols are quite clear, it often means that one or both machines have been incorrectly or incompletely programmed.

Service Unavailable. Your Web server is currently unable to handle the HTTP request due to a temporary overloading or maintenance of the server. The implication is that this is a temporary condition which will be alleviated after some delay. Some servers in this state may also simply refuse the socket connection, in which case a different error may be generated because the socket creation timed out.

Gateway Timeout. A server (not necessarily a Web server) is acting as a gateway or proxy to fulfil the request by the client (e.g. your Web browser or our CheckUpDown robot) to access the requested URL. This server did not receive a timely response from an upstream server it accessed to deal with your HTTP request.This usually means that the upstream server is down (no response to the gateway/proxy rather than that the upstream server and the gateway/proxy do not agree on the protocol for exchanging data.

HTTP Version Not Supported. Your Web server does not support, or refuses to support, the HTTP protocol version specified by the client

(e.g. your Web browser or our CheckUpDown robot) in the HTTP request data stream sent to the server.The HTTP protocol has various versions identified as major.minor e.g. version 0.9, 1.0 or 1.1. Your server is indicating that it is unable or unwilling to complete the request using the major version provided by the client - other than with this error message.Assuming that your request identifies a valid major.minor version number (the request is not fundamentally corrupt), then this error should mostly only occur if you are trying to use version 1.0 or 1.1, but your

Web server only supports the older 0.9 version.