Knowledgebase: General
Glossary of Common Terms
Posted by Maria Brosnan on 27 June 2016 05:26 PM


A generic name for a list of email addresses or IP addresses that are originating with known spammers.
Individuals and enterprises can use blacklists to filter out unwanted emails, as most email applications today have filtering capabilities.  Also referred to as a blackhole list, the blacklist also can include ISPs that allow known spammers to use their services.


A program which allows a person to read hypertext. The browser gives some means of viewing (or listening to) the contents of pages and of navigating from one page to another.


Generic top-level domain. The most commonly used TLD on the Web.


Country code Top Level Domain. Also referred to as non-US ISO country codes. Some countries register all domains at the top level, e.g. Germany (.de) and Norway, while others create additional structure with Second Level domains (2LDs) such as (New Zealand), (Japan), (Taiwan), etc.


A distributed database of information that is used to translate domain names, which are easy for humans to remember and use, into Internet Protocol (IP) numbers, which are what computers use to find each other on the Internet.  People working on computers around the globe maintain their specific portion of this database, and the data held in each portion of the database is made available to all computers and users on the Internet. The DNS comprises computers, data files, software, and people working together.

Domain Name

In short, a domain name is nothing more than an alias for a numeric web address. Each web site on the internet has a numeric address that functions like coordinates on a map. Instead of pointing to a geographic location on earth, these numeric addresses, called IP addresses, point to a graphical location on the Internet. Computers have no problems with locating and remembering numeric addresses. In contrast, most humans have trouble remembering long, complicated sequences of numbers. So, to make surfing the web easier, the domain name system was invented. This system allows people to use easy to remember names for web sites instead of those number sequences.

Email Aliasing

The practice of having multiple email addresses all resolve to a single email address. For example: a small business has an employee with the email address This person is responsible for the sales and customer service of the company which have the separate email addresses and to handle the business of those divisions. Mail coming in to those two email addresses will be forwarded by a mail relay to the email address so that the employee does not need to check three separate email accounts to read the messages that are sent to the three different addresses.

Email Client

An application that runs on a personal computer or workstation and enables you to send, receive and organize email. It's called a client because email systems are based on a client-server architecture. Mail is sent from many clients to a central server, which re-routes the mail to its intended destination.

Email Spoofing

Forging an email header to make it appear as if it came from somewhere or someone other than the actual source. The main protocol that is used when sending email, SMTP, does not include a way to authenticate.  There is an SMTP service extension (RFC 2554) that allows an SMTP client to negotiate a security level with a mail server. But if this precaution is not taken anyone with the know-how can connect to the server and use it to send spoofed messages by altering the header information.

Fully-qualified domain name

A fully-qualified domain name (FQDN) is that portion of an Internet Uniform Resource Locator (URL) that fully identifies the server program that an Internet request is addressed to. The FQDN includes the top-level domain name, the second-level domain name and any other levels. An FQDN should be sufficient to determine a unique Internet address for any host on the Internet. The prefix "http://" added to the fully-qualified domain name completes the URL.


File Transfer Protocol. The Internet engineering standard for transferring files from one computer to another i.e. from a web creator's computer files to the virtual server or vice versa. Such a transfer is made via a special FTP software program such as WS_FTP or CuteFTP. There are many Internet sites that have established publicly accessible repositories of material that can be obtained using FTP, by logging in using the account name anonymous, thus these sites are called anonymous ftp servers.


Generic Top Level Domain. In the US, gTLDs used to describe organisational and political structures and are usually given three-letter names. Over the past few years, a number of these gTLDs have become "unrestricted" i.e. anyone can register a domain in that gTLD. You do not even have to reside in the US or be a business entity. For domains outside the US, two-letter ISO (International Organization For Standardization) country codes are used.  Examples of gTLDs are .com, .net and .org.


Documents on the Internet are written in a simple "markup language" called HTML, which stands for HyperText Markup Language. HTML looks a lot like old-fashioned typesetting code, where you surround a block of text with codes that indicate how it should appear, additionally, in HTML you can specify that a block of text, or a word, is linked to another file on the Internet. HTML files are meant to be viewed using a browser, such as Netscape or Internet Explorer.


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).


Term coined by Ted Nelson around 1965 for a collection of documents containing cross-references or "links" which, with the aid of an interactive browser program, allow the reader to move easily from one document to another.


Internet Assigned Numbers Authority. The function that currently oversees registration for various Internet Protocol parameters, such as port numbers, protocol and enterprise numbers, options, codes, and types. The IANA function is currently located at the Information Sciences Institute at the University of Southern California in Marina del Rey, CA.


Internet Corporation for Assigned Names and Numbers. ICANN is the non-profit corporation that is assuming responsibility for coordinating certain Internet technical functions, including the management of Internet domain name system. More information about ICANN can be found at their web site, which is posted at:


Short for Internet Message Access Protocol, a protocol for retrieving email messages. The most commonly used version, IMAP4, is similar to POP3 but supports some additional features. For example, with IMAP4, you can search through your email messages for keywords while the messages are still on the mail server. You can then choose which messages to download to your machine.

IP Address

Every machine that is on the Internet has a unique IP number - if a machine does not have an IP number, it is not really on the Internet. Most machines also have one or more domain names that are easier for people to remember. IP addresses are numerical, often 32-bit addresses that are expressed as four numbers between 0 and 255, separated by periods, for example:

For more information, has an easy to comprehend article here on how Web Servers Work.

ISP (Internet Service Provider)

Internet Service Provider. While rather a generic term, ISP generally refers to a person, organization, or company that allows its users access to the Internet. In addition to Internet access, many ISPs provide other services such as web hosting, DNS and other services.


Sometimes called a "host." 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 nameservers hosted on separate networks.


When a registered domain is parked, the domain is reserved but remains inactive. A temporary Web page is displayed until the site is unparked or activated. Domain name parking is often used by registrants who do not yet have a hosting provider or who haven't yet built a site for the domain.


The individual or organization that registers a specific domain name. This individual or organization holds the right to use that specific domain name for a specified period of time, provided certain conditions are met and the registration fees are paid. This person or organization is the "legal entity" bound by the terms of all applicable domain registration Service Agreements.


An entity with a direct contractual relationship with, and special access to, a registry, that inserts records on behalf of others.


A database associating DNS information with some person, legal entity, operational entity, or other reference.


The top of the domain name System hierarchy. Often referred to as the "dot."

Second-Level Domain

In the domain name System, the next lower level of the hierarchy underneath the top level domains. In a domain name, that portion of the domain name that appears immediately to the left of the top-level domain. For example, the domainsforbeginners in Second-Level Domains are the focus of domain speculators and have been the root of a good portion of internet name disputes on the internet. It's important that your second-level domain does not infringe upon the registered trademark of another entity.


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 WWW server, or to the machine on which the software is running, e.g. our mail server is down today, that's why email isn't getting out. A single server machine could have several different server software packages running on it, thus providing many different servers to clients on the network.


Top Level Domain. In the domain name System (DNS), the highest level of the hierarchy after the root. In a domain name, that portion of the domain name that appears furthest to the right. For example, the com in


Uniform Resource Locator. An internet "address." A draft standard for specifying the location of an object on the Internet, such as a file or a newsgroup. They are used in HTML documents to specify the target of a hyperlink which is often another HTML document (possibly stored on another computer). e.g. The first part of the URL, before the colon (often http), specifies the access method. The part of the URL after the colon is interpreted specific to the access method.

URL Forwarding

Also called URL Redirection or Website Redirection. In short, when the user types in one address (URL) for a web site and is then redirected to a site, often on a different server than the domain. Often the URL name entered will be short, easy to remember URL while the destination page is actually defined by a much longer, harder to remember URL. It occurs when a Web server tells the client browser to obtain a certain requested page from a different location. The new URL may be on the same server or a different one and may itself be subject to redirection. The user is normally unaware of this process except that it may introduce extra delay while the browser sends the new request and the browser will usually (although not always) display the new URL rather than the one the user originally requested.

Virtual host

Also called an IPP. In order to establish a full-time presence on the internet, one needs to have computers that are connected continuously to the Internet. Special hardware and software are needed as well as constant maintenance of a full-time high speed connection to the internet. A virtual host provides services to relieve ts hosted customers from the burden of dedicating costly hardware/software and valuable human resources to its web presence effort. Because the electronic frontage (or website) actually resides on the IPP's computers, and not that of the entity, it's virtual. This is where the name "virtual host" comes from.

Web Mail

Web mail is a Web page interface used to access email through a Web browser. In order to use Web mail your mail Provider needs to provide this service, or you can get a subscription to an Internet Web mail service some free, some paid subscriptions). Web mail is a secure Web page that you load in your Web browser and log in by entering your username and password. Web mail is popular as it allows you to send or receive email from anywhere, so long as the computer you are using is connected to the Internet and has a Web browser. It is an excellent option for those travelling or working outside the office.

Web Page

Simply, a block of information running on a web server identified by a specific URL. Such pages are most often written in HTML. It is also possible for a server to create a dynamic web page via special scripts.

Web Site

Simply put, a block of information running on a web server. A web site may or may not of a group of pages related to one another, and is identified by its Second-Level Domain.


A searchable database maintained by the registrar, which contains information about networks, networking organisations, domain names, and the contacts associated with them for respective domains. Also, the set of rules that describes the application used to access the database.