Computer Lingo

Computer lingo is a language all it's own. Often, we find ourselves explaining to our customers what various terms mean. We admit that in the rapidly changing world of computers and Internet, terms are being created every day.

While building this site, we found that we were using terms that some folks might not be familiar with. As a result, we've created this page to provide some definitions. Our definitions are our own -- no definition has been taken from other terminology sources or dictionaries.

Throughout the rest of our site, you may find certain terms underlined. These underlined terms link to this page and take you to the section that defining the term. If you should find terms on pages that do not have links to this page, or if you find a that definition is not clear, is inaccurate, or could be worded more clearly, please feel free to fill out our quick and simple contact form and point it out to us.

DNS — domain name system. The domain name system was invented to make network computers easier to locate for humans. The DNS system is a distributed database that maps human readable addresses into IP addresses (see IP Address below). When you pull up your browser and type in, your computer sends a request to the DNS server that it is configured to use. If that DNS server doesn't have an entry in it's database for, it sends out a request to another DNS server to get the information. This process repeats itself until the information is found. Typically, if a DNS server doesn't have an entry in it's system for an address, it will go ahead and store it into it's database once it has been found so that next time, it doesn't have to "ask around" for it. Eventually, the DNS information is found and then returned to your computer. The information contains the IP address that's required to locate on the Internet. The IP address for at the time of writing was Once your browser has received this IP address from the DNS system, it automatically sends out a request for the web site located at The DNS is in place so that you don't have to type into your browser to find Apple's web site.

Firewall — network traffic discriminator. Firewalls have the ability to block incoming and outgoing traffic on a network or a computer. Firewalls exist as both software and hardware. For example: Mac OS X has a firewall built in to it. Small businesses, large corporations and everything in between generally opt to employ a hardware firewall -- a device that is placed in between to critical points on the network such as their servers and the Internet.

IP Address — unique network identifier. In order for computers to communicate over the network (local or Internet), each computer must have a unique address. The most synonymous example to this would be your home address and the postal service. Your home address is unique in the world, so the postal service is able to deliver mail to you with great accuracy. IP addresses are a sequence of numbers like or No two computers on the same network or Internet have the same IP address simultaneously. (see DNS and Router for more information)

Port Forwarding — allow specific service(s) through a firewall. By nature, port forwarding applies when you have multiple routers on a network and/or a firewall in place. A firewall restricts access to network services. Port forwarding is a configuration directive or rule for a firewall or router's behavior. In a simple example, you have DSL Internet service and your DSL modem acts as a firewall blocking incoming network traffic on most or all ports. You want to set up one of your computers as a web server. Web service typically operates on port 80 (see Port Number below). You would configure your DSL modem to forward requests on port 80 to your internal IP address assigned to your web server.

Port Number — sub-division of computer address. Computers on the Internet are identified uniquely based on an address called an IP address. Since there are a variety of different Internet services, computers need an identifier (port number) to discern which software on the computer should process the request. That's where port numbers come in. Port numbers are like apartment numbers on a computer only the apartments are different pieces of software. When you open up your web browser and type in a web address like "" and press enter, your computer sends out a request to a DNS server (on port 53) to find out what the IP address is for (see DNS for more information). Once your computer has received the IP address for, your browser which automatically resends the request for the web page out to the IP address plus the port number 80 ( On Apple's end, the web servers receive the request for their home page on port 80 which tells the computer to pass the request to their web server software which processes your request and sends the HMTL and images back to your browser.

Router — network traffic controller. Routers are like network traffic controllers. They pass data that's coming in on toward it's intended destination. When network data passes between computers (either locally or over the Internet) routers function like roadway intersections, only smarter. Routers examine the incoming data for it's destination, then intelligently pass it along to or toward that destination. Internet data typically transfers through a half dozen or more routers before it gets from starting point to ending point. Routers exist as both dedicated hardware and in software.

Your Lingo (terminology feedback)

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