
Basic Network Configuration
14
Domain Name Server (DNS)
A DNS Server is an Internet service that translates domain names (for example, in the URL
http://www.telex.com, the domain name is the telex.com) into IP Addresses. The Internet is
based on IP Addresses which are numeric and since domain names are alphabetic, they are
easier to remember. Every time a domain name is used it must go through the DNS server to be
translated into an IP Address.
Gateway
A gateway is a node on a network that serves as an entrance to another network. The gateway
routes traffic from a computer to an outside network that is serving the web pages. For
example, the gateway for a home computer is the ISP provider that connects the user to the
Internet.
In a corporate environment, the gateway often acts as a proxy server and a firewall. Gateways
are similar to routers and switches in that they forward data to the destination and provide the
path for which the data will travel to the destination.
Hub
A hub is a common connection point for devices in a network. A hub has multiple ports. When a
data packet arrives at a hub, it is copied and distributed to all of its ports so that all nodes on the
LAN can see the packets.
There are three types of hubs:
passive hub - this hub serves as a conduit for the data, enabling it to go from one device to another.
intelligent hub (also known as manageable hubs) - this hub includes addition features that enable
administrators to monitor traffic through the hub.
switching hub - this hub reads the destination address of each packet and then forwards the data
pack to the appropriate port.
IP Address (Internet Protocol Address)
An IP Address is an identifier or numerical name for a computer or device on a network. Data
between computers are routed over the network using these addresses to identify the computer
the message is being sent to and the computer the message is being sent from.
The format of an IP Address is a 32-bit numeric address written as four numbers separated by
periods. For example, an IP Address looks like 10.100.1.1.
IMPORTANT: When working within an isolated network (meaning there is no Internet
access), IP Addresses can be assigned at random just as long as they are unique to each
computer and device. When the isolated network is connected to the Internet, registered
Internet Addresses must be obtained. This is to prevent duplication of addresses.