What is TCP/IP?
For many beginning networker's TCP/IP is a formidable concept, but we're going to try to keep it
simple. Simply put, TCP/IP is the network communication protocol suite of the Internet. Networks move traffic based
upon communications rules known as protocols, the language of networks. TCP/IP contains a multitude of other
protocols designed to support various network communications. When you send an email, Simple Mail Transport
Protocol (SMTP) handles the communications with your mail server to send the mail out of your system, for retrieve
your email, the Post Office Protocol Version 3 (POP3) manages the retrieval of your messages. When you browse the
Internet Hypertext transport protocol manages the movement of information for your request to the responses the
Internet servers may provide. Simply put, for everything you do on the Internet, a protocol is in place to manage
the sending and receiving of information to and from your computers and network so you don't have to worry about
So What's Important To Know About TCP/IP?
For the purposes of managing your Local Area Network (LAN) you really only need to understand a few basic
concepts. Your LAN is the only network you actually have any control over and is hence the only one you have to
worry about maintaining. With the connection of your LAN to the Internet you open your network to communications
with the largest Wide Area Network (WAN) available to humanity today. Your connection to the Internet is made via a
Cable, DSL, Satellite, or phone line modem which manages the routing of traffic to and from your LAN to the wide
array of Internet resources available. These devices fall into a functional category of devices known as routers.
Routers, as the name implies, route traffic in and out of your network so you can enjoy the benefits of this
So What's Important To Know About TCP/IP and My LAN?
Basically you only need to configure a few things on your LAN for communication to occur:
IP Address: An IP address is a specific network address assigned to an individual computer. IP addresses must
always be unique and now to machines on the same network are allowed to share an IP or a network conflict will
occur. To simplify the management of your network, we recommend you only use the Class C network range of
192.168.0.X, where X is the unique IP address of your individual machine between 1 and 254. This range of IP
addresses are special in that the range is reserved for private networks that cannot route traffic directly on the
Internet. However, this private network range can connect and communicate to the Internet thanks to the routing
functionality of your modem and in most cases a router which may also provide firewall and wireless networking
functionality. As well, wireless routers available today can also provide a service called Dynamic Host
Configuration Protocol which can automatically assign IP addresses to your systems so you don't have to. By
configuring DHCP on your wireless router adding new devices such as computers, PDAs, cell phones, and Internet
enabled multimedia devices is a snap simplifying your network management needs.
Subnet Mask: This is an easy topic to go off the technical deep on with so, as usual, we'll try and keep it
simple. In advanced and complex networks, networks can be divided to allow for more granular management. This may
be based on the need to segment networks for security and various other reasons. For the purposes of your LAN using
the 192.168.0.X class C network space, the subnet mask will always be 255.255.255.0 to allow you the full range of
IP addresses within that space.
Default Gateway: The default gateways is the IP address of your router, or more appropriately, where your
network will go to find resources outside of your network. Your router will actually have two IP addresses assigned
to it, a LAN (internal) IP address such as 192.168.0.254, and an Internet routable (external) IP address assigned
by your Internet service provider. To simplify the maintenance of your LAN it is recommended that you use either
192.168.0.1 or 192.168.0.254 as your gateway address to make it easy to remember. While you can make it any number
between 1 and 254, picking an IP at the beginning or end is much easier to remember than say 67, and will make your
management task easier to handle.
DNS Server: Your IP configuration may have one or more Domain Name Servers (DNS) configured to manage system
lookups on behalf of your internal systems. A DNS server is to computers what a card catalog is to a library. To
make things simple for people DNS provides the lookup functionality to make connecting to a server easy for human
beings. For example, lets say you wanted to connect to the World Wide Web Consortium website, as a user you simply
enter in their URL http://www.w3.org/ and your browser takes you to the
website. From the perspective of your computer, it doesn't know what an www.w3.org means and so relies on a DNS server to provide the IP address for this
server. Thus in reality what happens is you would enter www.w3.org into your
browser, your computer, not know what this means will issue an DNS request to the w3.org domain asking who
www.w3.org is. Their DNS server will return an IP address to your system,
as of this writing the address is 184.108.40.206, then your browser understands what system it needs to talk to in
order to retrieve the information you are seeking. Usually this information will be provided by your Internet
Service Provider (ISP) and you can enter the address(es) into your system for proper DNS resolution. If you
don't know specifically what these IP addresses are all is not necessarily lost. Most modern home routers will
provide DNS forwarding functionality on your behalf allowing you to enter your default gateway as the DNS server
and still function.
While the TCP/IP protocol suite contains a vast array of networking protocols, one does not have to be an expert
in the individual protocols to successfully connect their LAN to the Internet, one simply needs to have an IP
address, subnet mask, default gateway, and DNS servers configured and let the protocols do all of the heavy