Glossary Term D - Web Hosting Glossary
An ISDN D or Data channel is a data connection between the telephone company's switching equipment and their customer's ISDN equipment. It carries telephone connection information--signals to tell your equipment that a call is coming in and carry dialing and call handling information to the phone company's equipment--and can also be used to carry multiple low-speed data connections using the X.25 packet-switching protocol.
In general, any outward bound traffic from a web site, with the exception of e-mail, is considered to be data transfer. For example, each time a web page, image, midi file, quicktime video, etc. is loaded, data transfer is generated. Each of our plans includes a generous amount of free data transfer which should be more than enough for most sites. In fact, 98% to 99% of our customers operate within their free data transfer allowance. Additional data transfer beyond the threshold will incur a small charge.
Related information stored in one location in a digital format. Dependant upon the software used to manage a database, minimally, information can be added to, retrieved from and sorted. On the internet databases are used to build dynamic web sites. Some popular database software titles are mySQL, SQL, Oracle, and Access.
A dedicated server is a computer that only runs one type of server software, and is usually constructed according to the user's specifications. Dedicated servers are typically used for websites that have high traffic, and need many resources and much processing power.
The ability of an object to issue a message to another object in response to a message. Delegation can be used as an alternative to inheritance.
DES - Data Encryption Standard
Data Encryption Standard. A commonly-used standard method for encrypting and decrypting data. Encryption is necessary, as valuable and sensitive information is often sent from one computer to another via a network that technically can be accessed by anybody. It provides a degree of security should the information fall into the wrong hands. DES was developed by the U.S. National Institute of Standards & Technology.
DHCP - Dynamic Host Control Protocol
Dynamic Host Control Protocol. An effective way to dynamically assign and reuse a fixed number of IP addresses when there are more devices on the network than addresses available. A DHCP server dynamically assigns IP addresses to devices requesting them. These address assignments expire after a time specified by the network manager. The DHCP server then reassigns these addresses to other devices as needed. DHCP is an extension to BOOTP in which the address assignments are static.
The next generation of HTML, the language that specifies exactly how text and images will be displayed on a web page. Dynamic HTML, developed by Netscape and the World Wide Web Consortium (W3C), is based entirely on industry-standard HTML and Java. New features in Dynamic HTML, such as absolute positioning, give designers and developers greater control over the look and feel of web pages.
Dialup Access or a Dialup Account is the use of your PC in connection with your modem and a telephone line to gain access to the Internet. This is contrasted with an always-on connection for a set of computers in an office network such as a local area network (LAN), which has a direct connection to the Internet.
A diesel-powered generator used by hosting companies as a back-up source to generate electricity in the event of a power outage. This is a very common feature at most web hosting data centers to provide the ultimate in redundancy. Many data centers are also equipped with dual power sources coming from two different points on the cities power grid to provide yet another level of redeundancy.
Dig - Domain Information Groper
A flexible tool for interrogating DNS name servers. It performs DNS lookups and displays the answers that are returned from the nameserver(s) that were queried. Most DNS administra tors use dig to troubleshoot DNS problems because of its flexibility, ease of use and clarity of output. Other lookup tools tend to have less functionality than dig. Although dig is normally used with command-line arguments, it also has a batch mode of operation for reading lookup requests from a file.
A Microsoft Windows API designed to provide software developers with direct access to low-level functions on PC periferals. Before DirectX, programmers usually opted for the DOS environment, which was free of the limited multimedia feature set that characterized Windows for many years.
This is how you describe the capacity to store information locally or remotely. If you only have 10 megabytes of "Free" disk storage space, and have a program you wish to install that requires 20 megabytes of free disk space, you must free up at least another 10 megabytes of disk space in order to be able to store or install the program to a storage device. Disk space is measured in everything from bits to terabytes.
DNS - Domain Name System
A database system that translates an IP address into a domain name. DNS maintains this database for resolving host names and IP addresses. This allows users to specify remote computers by host names rather than numerical IP addresses.
DNS stands for Domain Name Server. These are the servers that match up a fully qualified domain with the proper IP address. This is necessary because computers only understand the IP address for your domain (e.g.- 123.45.678.90).
Assuming the DNS name of another system by either corrupting the name service cache of a victim system or by compromising a domain name server for a valid domain.
Domain locking prevents your domain name from being hijacked or accidently transferred. If a transfer to another registrar or hosting company is requested for a locked domain name the transfer request will automatically fail. If you wish to transfer a locked domain name you simply have to login to your control panel and unlock the domain name.
A whois query of a domain to view the contact information of the domain name owner. Typically the Admin, Technical, Owner record, and the DNS info can be viewed.
Domain Name System
The domain name system is a distributed database arranged hierarchically. Its purpose is to provide a layer of abstraction between other Internet services (web, email, etc.) and the numeric addresses (IP addresses) used to uniquely identify any given machine on the Internet.
Domain names are the word sequences users enter in their URL bar to visit your site. They are attached to a DNS, short for Domain Naming System, which is used to translate numeric addresses (known as IP, or Internet Protocol, addresses) into words. Each site you visit on the net has a numeric IP address behind its name.
All domain names have to be stored on a server in order to be purchased. Most domain registration services will therefore temporarily place a newly purchased name on their servers until a hosting plan is purchased or the owner points the DNS to a different site. This is known as parking.
Similar to a hosting reseller, only this time the person or company signs up with a registrar to obtain domains at a lower price in bulk and can offer those at any price they determine to the end user.
Any zone that isn't a reverse zone. Root is an exception; root is not a domain zone. Sometimes called a forward domain, or forward zone.
A domain name extension intended for businesses online.
A domain name used by commercial enterprises. When used as the last part of an address (as in "www.yahoo.com"), it indicates that the addressee is a company and not an organization (.org), a school in the U.S. (.edu) or an American government agency (.gov).
Domain name extension that is meant for use by informational and reference sites.
Domain name extension that is meant for use by individuals.
A Generic Top Level Domain that is meant for use by anyone.
A Generic Top Level Domain that was meant for non-profit organizations (not required).
A domain extension sponsored by Verisign. Meant for use in entertainment.
Domain name extension sponsored by NeuStar. Meant for use by residents and citizens of the United States.
Domain name extension that was original meant for Western Samoa, but has been promoted more for "Web Site".
Length of time a web server is offline or "down".
A WYSIWYG html editor and much more. Created by Macromedia. Very similar to Golive and FrontPage. Dreamweaver, like Golive, can create many different code types and save as different file types.
DSL - Digital Subscriber Line
Short for Digital Subscriber Line. This is technology that uses ordinary copper telephone lines to provide Internet speeds ranging from 1.5 to 9 Mbps--speeds that are 30 to 50 times faster than a regular 56-kbps dial-up modem. DSL also allows users to receive voice and data simultaneously, since the signal is carried on a higher frequency than normal telephone communications. xDSL refers to all types of Digital Subscriber Lines, including: ADSL: Asymmetric Digital Subscriber Lines SDSL: single-line digital subscriber lines HDSL: high-data-rate digital subscriber lines VDSL: very-high-data-rate digital subscriber lines
Dynamic IP Address
A Dynamic IP address is one that is temporarily assigned to a user by their internet service provider every time the connect. This cuts down on the number if IP addresses large consumer providers need because not all of their customers are using the service at any given time. It also cuts down on bandwidth usage by preventing consumers from hosting servers.