Please refer to the glossary for a brief description of commonly used terms in relation to the Internet, Web Development and Networking technologies.
Asymmetric Digital Subscriber Line: a form of Internet connection that provides more bandwidth in one direction than the other. Bandwidths of up to 2Mbps are available with a maximum upload speed of up to 256kbps. See also ISDN.
American Standard Code for Information Interchange. ASCII is the most common format for text files used in computing and on the Internet.
In an ASCII file, each alphabetic, numeric, or special character is represented with a 7-bit number (a string of seven 0s or 1s) and 128 possible characters are defined. Conversion programs allow different operating systems to change a file from one code to another.
ASCII was developed by the American National Standards Institute.
A measure of the capacity of a telecommunications link: the greater the bandwidth, the more information can be communicated during any given period.
A modem that works at 57,600 bps (bits per second) has twice the bandwidth of a modem that works at 28,800 bps.
For example, it takes more bandwidth to download a photograph in one second than it takes to download a page of text in one second. Large sound files, computer programs, and animated videos require still more bandwidth for acceptable system performance.
An individual or custom-made product or service. Traditionally applied to custom-tailored clothing, the term has been extended to information technology, especially for custom-designed software.
A malicious hacker who exploits - or publicises - a security weakness before informing the affected organisation.
Buffer overflow attack
Buffers are used whenever data is received in sizes that may be different than the ideal size for specific hardware or software; if buffer sizes are not optimised and strictly delimited, hackers can insert their own program code into vulnerable software (including operating systems) causing widespread or wholesale malicious damage. Buffer overflow attacks are the most common and serious form of malicious attack.
(Common Gateway Interface) - a set of rules that describe how a web server communicates with another piece of software on the same machine, and how the other piece of software (the "CGI program") talks to the web server.
A CGI program is a small program that takes data from a web server and does something with it, like putting the content of a form into an e-mail message, or turning the data into a database query. Any piece of software can be a CGI program if it handles input and output according to the CGI standard.
A software program that is used to contact and obtain data from a server software program on another computer, often across a great distance. Each client program is designed to work with one or more specific kinds of server programs, and each server requires a specific kind of client. A web browser is a specific kind of client.
Cookies enable web sites to remember your previous visits, in the same way that a shopkeeper will remember your face when you visit the shop.
Cookies are unique pieces of information (such as pages in a web site you have visited, your online shopping transactions, or registration information that you have provided) that are sent by a web server to your browser and stored on your hard drive, often in a coded form to reduce their size. When you re-visit the web site, the web server reads the cookie stored on your computer, this enables the site to recognise you.
Denial of Service (DoS)
An attack on a network designed to render it - or an Internet resource - unavailable. The target may be an organisation's e-mail services or its website.
(Domain Name System or Service), an Internet service that translates domain names into IP addresses. Every time you use a domain name, a DNS service translates the name into the corresponding IP address. For example, the domain name www.example.com might translate to 220.127.116.11.
A name that identifies one or more IP addresses. Domain names are used in URLs to identify particular web pages. For example, in the URL http://www.power.net.uk/index.html, the domain name is power.net.uk.
Every domain name has a suffix that indicates which domain type it belongs to. There are only a limited number of such domains. For example:
- gov - Government agencies
- org - Organisations
- com - Commercial business
- net - Network organisations
A dotcom is a web site intended for business use, although it's also commonly used to describe an internet-based trading company. The term is based on the .com that forms the last part of the address for most commercial websites.
Dynamic html e-mails
This is a term we use to describe building an HTML e-mail communication where the text and image content differ from one individual to another, depending on lifestyle data, previous purchasing history and previous expressions of interest.
E-business (electronic business) is the conducting of business on the Internet, not only buying and selling but also servicing customers and collaborating with business partners.
E-commerce (electronic commerce) is the buying and selling of goods and services on the Internet, especially the World Wide Web.
An extranet is an internet that is partially accessible to authorised outsiders. Whereas an intranet resides behind a firewall and is accessible only to people who are members of the same company or organisation, an extranet provides various levels of accessibility to outsiders. You can access an extranet only if you have a valid username & password, which determine the parts of the extranet you can view.
Extranets are becoming a very popular means for existing business partners to exchange information.
(Frequently Asked Questions) - FAQs are documents that list and answer the most common questions on a particular subject.
An Internet software tool for locating people on other Internet sites. Finger is also sometimes used to give access to non-personal information, but the most common use is to see if a person has an account at a particular Internet site. Many sites do not allow incoming Finger requests, but many do.
A form of Internet security that typically stands between a private network and the external Internet (although internal firewalls are also now increasingly common) and is designed to prevent unwanted traffic from passing.
(File Transfer Protocol) - a method of moving files directly from one computer to another across a network. FTP is an unencrypted protocol - data is not protected during transmission.
As used in reference to the World Wide Web, "hit" means a single request from a web browser for a single item from a web server; thus in order for a web browser to display a page that contains 3 graphics, 4 "hits" would occur at the server: 1 for the HTML page, and one for each of the 3 graphics.
"Hits" are often used as a very rough measure of load on a server, e.g. "Our server has been getting 300,000 hits per month." Because each "hit" can represent anything from a request for a tiny document (or even a request for a missing document) all the way to a request that requires some significant extra processing (such as a complex search request), the actual load on a machine from 1 hit is almost impossible to define.
Originally, the web page that your browser is set to use when it starts up; This term is often now used simply to refer to the main page out of a collection of web pages.
HyperText Mark-up Language, the language originally invented to allow World Wide Web pages to be created. HTML e-mails go beyond plain text, and allow the inclusion of logos, rich colour images and animations as well as the clickable links that give the web its interactive character.
(HyperText Transfer Protocol) - The protocol for moving hypertext files across the Internet. Requires a HTTP client program on one end, and an HTTP server program on the other end. HTTP is the most important protocol used in the World Wide Web (WWW).
Generally, any text that contains links to other documents - words, phrases or images in the document that can be chosen by a reader and which cause another document to be retrieved and displayed.
A private network inside a company or organisation that uses the same kinds of software that you would find on the public Internet, but that is only for internal use.
As the Internet has become more popular many of the tools used on the Internet are being used in private networks, for example, many companies have web servers that are available only to employees.
Note: an Intranet may not actually be an internet - it may simply be a network. See also extranet.
(Internet Protocol Address) the unique number (consisting of 4 parts separated by dots, eg 18.104.22.168) that defines the address/location of a PC on a network.
An IPS Tag is the case sensitive label that applies to each ISP and is required to transfer domain names from one ISP to another. All ISPs are allocated these tags when they apply to become an ISP.
Internet Relay Chat, a system whereby you can carry out (text-based) live "conversations" with other computer users.
Integrated Services Digital Network: a communication network closely associated with the public telephone network but allowing data to be transferred at speeds up to 128k per second.
Internet Service Provider. A company that connects users to the Internet, sometimes referred to as an On-line Service Provider or Access Provider.
(Local Area Network) - A computer network limited to the immediate area, usually the same building or floor of a building.
Refers to a communications line that is rented for exclusive 24-hour, 7-day-a-week use from your location to another location. The highest speed data connections require a leased line.
Mail mapping or mail forwarding is the process of linking your e-mail address or addresses and website to your domain name.
(MOdulator, DEModulator) - A device that you connect to your computer and to a phone line, that allows the computer to talk to other computers through the phone system.
A number of computers or PCs linked together allowing sharing of programs, data and printers.
This is the company that registers international domain names.
The name for discussion groups on USENET.
Any single computer connected to a network.
This is the company that registers all UK domain names.
Network Terminating Equipment: any piece of equipment at the end of a communication link.
An operating system (abbreviated as 'OS') is the program that manages all the other programs in a computer.
The individual pieces (or collections of bits) into which data is broken down for transmission over networks. Each packet carries destination address information, and packets are typically transmitted in a stream.
(Personal Digital Assistant) - a single mobile device that performs the traditional functions of a number of separate devices - such as an organiser, mobile phone or personal computer - often with the added value of internet connectivity.
Peripheral devices are hardware items that can be attached to a computer e.g. mouse, monitor, keyboard, printers, modems etc.
"ping" is a utility that allows you to determine whether a specific IP address is available. It works by sending a packet of information to the specified address and waiting for a reply, or "echo". PING is used primarily to troubleshoot Internet connections.
Post Office Protocol is a delivery agent and refers to the way e-mail software such as Outlook collects mail from a mail server.
(Point to Point Protocol) - a protocol that allows a computer to use a regular telephone line and a modem to make TCP/IP connections.
An agreed standard or method of communication of information; unless two computers are configured to accept the same protocol(s), information cannot be passed between them.
A computer or other network device used to pass requests, handle functions or information (such as requests to view web sites) on behalf of one or more other computers; application-specific proxies are frequently deployed within firewall configurations to enhance security.
A relational database is organised into tables, in which data is defined so that it can be reorganised and accessed in a number of different ways without having to reorganise the database tables.
Special-purpose network equipment (or software package) that handles the connection between two or more networks. Routers spend all their time looking at the destination addresses of the packets passing through them and deciding which route to send them on.
A computer, or a software package, that provides a specific kind of service to client software running on other computers. The term can refer to a particular piece of software, such as a web server, or to the machine on which the software is running. (eg Our mail server is down today, that's why e-mail isn't getting out)
A single server machine can run several different server software packages, thus supporting many different clients on the network.
An establishment of communication between two computers to transmit data.
(Simple Mail Transfer Protocol) - is a mail forwarding agent that is the predominant Internet standard for the transmission and receipt of e-mail, including support for file attachments.
A term used to describe the sending of unsolicited e-mails, usually marketing goods or services, where permission has not given by the recipient.
(Structured Query Language) - a specialised programming language for sending queries to databases. Most industrial-strength and many smaller database applications can be queried using SQL.
Each specific application will have its own version of SQL implementing features unique to that application, but all SQL-capable databases support a common subset of SQL.
(Secure Sockets Layer) - a protocol designed by Netscape Communications to enable encrypted, authenticated communications across the Internet.
URLs that begin with "https://" indicate that an SSL connection will be used. SSL provides 3 important things: privacy, authentication, and message integrity.
TCP/IP & TCP/UDP
(Transmission Control Protocol/Internet Protocol & Transmission Control Protocol/User Datagram Protocol). Protocols incorporating a client/server model of communication used to enable Internet connectivity.IP and UDP are both connectionless protocols, meaning that no session is required in order to send packets of data to the chosen destination.
IP and UDP are fast but may be unreliable over longer distances or low quality connections.
TCP however requires a session to be set up, and MUST connect to the destination computer before any information can be sent. Thus, if the destination machine does not receive all the data, it will request it to be resent.
Top level domain refers to the suffix attached to domain names. There are two types of top level domain names, generic Top Level Domains (gTLDs) and national Top Level Domains (nTLDs) giving a range of suffixes.
A virus-like computer program that appears harmless and benign but is actually malicious in nature. Trojan Horses can act immediately or lay dormant for protracted periods before wreaking havoc. Anti-virus programs can detect many Trojan Horses - although, unlike viruses, they do not actually replicate.
(Uniform Resource Locator) - URLs identify a particular web page or the address of any resource on the Internet (eg the URL http://www.powergroup.co.uk/ will locate the Powergroup website).
The first part of the address indicates which protocol to use, and the second part specifies the IP address or the domain name where the resource is located.
(Universal Serial Bus) - a hardware interface that connects computers to peripherals.
A worldwide system of discussion groups, with comments passed among hundreds of thousands of users. Not all USENET machines are on the Internet. USENET is completely decentralised, with over 65,000 discussion areas, called newsgroups.
A digital infection of a computer or network. Viruses do not exist as independent programs but are elements of code concealed within host programs.
(Virtual Private Network) - a group of computers connected over the Internet where communication between them is protected using encryption to effectively create a closed sub-group.
A typical example would be a company network with two offices in different cities. Using the Internet, the two offices merge their networks into one network, but encrypt traffic that uses the Internet link.
(Wide Area Network) - any internet or network that covers an area larger than a single building or campus.
(Wireless Application Protocol) - a technology that links mobile devices with the Internet. Currently most widely known in relation to WAP phones, the now widely available mobile phones with Internet facilities built-in.
Powernet are proud to work with clients in a variety of market sectors.