Terms Letter: D

D Channel
It is the data chanel of an ISDN connection. Its speed can be 16 or 64 Kbps

Data transfer
In context of web hosting, it is the total amount of data that has been transfered for a given period. The amount it being calculated based on the size of all files – HTML, images, video, audio, etc – that have been downloaded by the visitors of the website. Sites with rich multimedia content usually need more data transfer per month so you will most probably need to look for a web hosting plan with greater transfer limits.

Database
It is a collection of information stored in a structured format. The most popular and widely used ones are the relation databases. Most web hosting plans offer MySQL database support. Other databases offered are Access, MSSQL, Postgre, Oracle.

Dedicated Server
In the context of web hosting, it is a server located in a data center which serves the site(s) of a single customer. The user can use all of its resources, can install any programs that he wishes. It is like co-located server, however in this case you pay a rent for the server(physical machine) as well along with paying for bandwidth and the other expenses. Dedicated servers are suitable for large and popular sites that require great bandwidth allotments and server resources like space, CPU time, memory usage.

DES
Data Encryption Standard – a common algorithm used for encrypting data. It has been developed in 1977 by IBM

DHCP
Dynamic Host Configuration Protocol – commonly used in LAN networks it is a protocol that lets network administrators centrally manage and automate the assignment of IP Addresses on the corporate network. There is a DHCP server running which gives out IP addreses to the computers connected to a local network.

Dial up
Dialup access is method of connecting your computer to the Internet. This type of access is the slowest ones compared to ISDN, DSL, etc. Also when you are connected to the Internet – your phone line is busy as well.

DNS
Domain Name System. This is a system that translates a website name – e.g www.besthostratings.com – to an IP address or Internet Protocol address. The global DNS data is replicated on many DNS servers across the Internet, hence when you change your domain name DNS information, it takes a while (24-48 hours) to have the changes propagated worldwide.

Domain name
It is the name of your site. It is unique – there cannot be two sites with using one and the same domain name. Domain Names always have 2 or more parts separated by dots. The part on the right denotes the TLD(top level domain part). It can be .com, .net, .org while the other part is the actual name of your site. It is called SLD(second level domain name). The one responsible for the International TLDs is ICANN (Internet Corporation for Assigned Names and Numbers). There are also CC(country code) TLDs – e.g .uk, .fr, .it

Domain parking
Domain parking is the option to have more then one domain name pointed to a web site. Usually a parked domain name is a full alias of the main domain name of the site. A parked domain name shows the same content as the main one. With most web hosting providers you can have mailboxes on the parked domain name.

Domain pointers
These are considered additional domain names pointed to a web hosting account. Some web hosting plans provide the option to have several domain pointers pointed to subfolders on subdomains on your hosting account. Having domain pointers included in your plan gives you the option to host more than one site on a web hosting account.

Domain Registrar
A company that handles the registration of a domain name. There is a list of acredited registrars company available at ICANN Accredited Registrar List There are also Country level registrar companies. A list of registrars that handle each country code domain name extension can be found at IANA CC database

DOS attack
Denial of Service attack. A method of attacking a server by sending an abnormally high volume of requests over a network, which essentially slows down the performance of a server, such that the server is unavailable for any users.

DSL
Abbreviation for Digital Subscriber Line. This is a technology for connecting to the Internet over a regular phone line. However it is faster in times(30 to 50) compared to the dial-up method. A commonly discussed configuration of DSL allows downloads at speeds of up to 1.5 megabits per second

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