(1) Short for Domain Name System (or Service), an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to 198.105.232.4.
The DNS system is, in fact, its own network. If one DNS server doesn't know how to translate a particular domain name, it asks another one, and so on, until the correct IP address is returned.domain
A group of computers and devices on a network that are administered as a unit with common rules and procedures. Within the Internet, domains are defined by the IP address. All devices sharing a common part of the IP address are said to be in the same domainIP address
An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 1.160.10.240 could be an IP address.
Within an isolated network, you can assign IP addresses at random as long as each one is unique. However, connecting a private network to the Internet requires using registered IP addresses (called Internet addresses) to avoid duplicates.
The four numbers in an IP address are used in different ways to identify a particular network and a host on that network. The InterNIC Registration Service assigns Internet addresses from the following three classes.
Class A - supports 16 million hosts on each of 127 networks
Class B - supports 65,000 hosts on each of 16,000 networks
Class C - supports 254 hosts on each of 2 million networks
The number of unassigned Internet addresses is running out, so a new classless scheme called CIDR is gradually replacing the system based on classes A, B, and C and is tied to adoption of IPv6.
CIDR
Short for Classless Inter-Domain Routing, a new IP addressing scheme that replaces the older system based on classes A, B, and C. With CIDR, a single IP address can be used to designate many unique IP addresses. A CIDR IP address looks like a normal IP address except that it ends with a slash followed by a number, called the IP prefix. For example:
172.200.0.0/16
The IP prefix specifies how many addresses are covered by the CIDR address, with lower numbers covering more addresses. An IP prefix of /12, for example, can be used to address 4,096 former Class C addresses.
CIDR addresses reduce the size of routing tables and make more IP addresses available within organizations.InterNIC
A collaborative project between AT&T and Network Solutions, Inc. (NSI) supported by the National Science Foundation. The project currently offers the following four services to users of the Internet.
InterNIC Directory and Database Services - online white pages directory and directory of publicly accessible databases managed by AT&T.
Registration Services - domain name and IP address assignment managed by NSI.
Support Services - outreach, education, and information services for the Internet community managed by NSI.
Net Scout Services - online publications that summarize recent happenings of interest to Internet users (managed by NSI).
POP
1) Short for Post Office Protocol, a protocol used to retrieve e-mail from a mail server. Most e-mail applications (sometimes called an e-mail client) use the POP protocol, although some can use the newer IMAP (Internet Message Access Protocol).
There are two versions of POP. The first, called POP2, became a standard in the mid-80's and requires SMTP to send messages. The newer version, POP3, can be used with or without SMTP.(2) Short for Point of Presence, a telephone number that gives you dial-up access. Internet Service Providers (ISPs) generally provide many POPs so that users can make a local call to gain Internet access.
SMTP
Short for Simple Mail Transfer Protocol, a protocol for sending e-mail messages between servers. Most e-mail systems that send mail over the Internet use SMTP to send messages from one server to another; the messages can then be retrieved with an e-mail client using either POP or IMAP. In addition, SMTP is generally used to send messages from a mail client to a mail server. This is why you need to specify both the POP or IMAP server and the SMTP server when you configure your e-mail application.
MAJORDOMO
A free mailing list server that runs under UNIX. When e-mail is addressed to a Majordomo mailing list, it is automatically broadcast to everyone on the list. The result is similar to a newsgroup or forum, except that the messages are transmitted as e-mail and are therefore available only to individuals on the list.
Another popular mailing list server is LISTSERV.
INTERNET PROTOCOLS
ARP
BGP
BIND
BOOTP
CDF
CGI
CIDR
DHCP
DNS
DOM
FTP
HTTP
ICMP
IP
IP Multicast
IPng
IPsec
L2TP
Layer Two Forwarding
LDAP
MIME
NAT
NNTP
OSPF
RIP
Routing Information Protocol
RSVP
RTP
RTSP
S-HTTP
S/MIME
SMIL
SMTP
SOCKS
SSL
TCP
TCP/IP
TFTP
UDP
URI
UUCP
X.509
XML
World Wide Web WWW
A system of Internet servers that support specially formatted documents. The documents are formatted in a language called HTML (HyperText Markup Language) that supports links to other documents, as well as graphics, audio, and video files. This means you can jump from one document to another simply by clicking on hot spots. Not all Internet servers are part of the World Wide Web.
There are several applications called Web browsers that make it easy to access the World Wide Web; Two of the most popular being Netscape Navigator and Microsoft's Internet Explorer.