I understand perfectly.  You have struggled with a single PC and an analog modem connection for lo these many years.  You have watched PC prices plummet over the last few years, and your wife and maybe even your children are starting to poke around on your precious little PC.  Off!  Off! I say.  Maybe you sprung for a nice high speed connection using a cable modem or an ADSL modem a few years ago. 

Now you finally gave in and bought your wife a nice new PC [or maybe you bought yourself a shiny new PC, and decided to hand down your old PC.  Hey, I understand...].  Now one of the reasons your wife and child wanted that PC was to get on the Internet of course, so you are now faced with the problem of getting  BOTH PCs on the Internet.  This can be a daunting task.  This can also be a scary task.  If you don't do this stuff correctly, you can open your PC and your home network up for some very serious intrusions by some very evil people out there in Internet land.  This is not funny business.  You should read an understand some of the cautions in doing this. 

At the very least, make sure you have the XP firewall turned on.  For pres - SP2, make sure ICF turned on!  Go do this real quick!!!  New PCs these days will have XP SP2, and you will have the firewall already turned on.  Thank God....  But don't think you are home free!

But have no fear.  Here at PCCitizen University I shall teach you all the innards and outards of all this networking gobbledygook.  It is being done by millions of people every day.  We need to help you do it correctly, and safely!

In case you are already a geek and understand basic networking, you should probably just go to the Windows networking section, where you will find some help to get the particulars of windows networking up and running on your home network.

If you were somewhat smart, you have been running antivirus software and a firewall of some sort on that little PC connected to the Internet.  If you have not been doing this, then you should probably take the time to clean up your little PC, since it may have some serious problems.  And don't even think about putting that new little PC on the Internet without some consideration for what you are doing.  What......!  You have already done this?!  Well, thankfully it was probably an XP you just bought, so Microsoft is getting a little better about the security considerations.  Hopefully you agreed to turn on the XP firewall, (or  ICF for pres - SP2) and subscribe for the antivirus program that came with your PC?  And have you installed XP SP2 yet?

[This page also has a diagram of the typical setup.  You may want to refer to it as well as the following diagrams.]

I have made the simplest diagram possible to begin this course.  You must understand this diagram and the following three, or there is absolutely no hope for you!  Hey, it's OK.  Just a few things to learn here, and then you are on your way!

Notice on your "FirstBorn" that the actual Internet IP address is assigned to your PC.  If you have not a clue what an IP address is, you should probably go here (well, maybe you should wait till you read this page.....) for a little tutorial.   The IP address is your phone number on the world wide web, but it is a special kind of phone number.   An "authorization" process is required to obtain an IP address.  In cable modem service authorization is usually performed by the PC or the NAT/router performing a "DHCP" attempt to the ISP server, wherein the MAC address is presented to the ISP.   For ADSL service, there is usually a username and password presented, exactly like dial-up service has been done all these many years.  The device that does the authorization is the device that actually receives the IP address.  Hackers and Internet terrorists can come knocking on that IP address "door," and they can GET IN if your PC is not properly configured! Don't worry about "MAC" addresses or NAT/routers just yet.  Those are just terms I threw in there to impress you.....

You may have had to acquire an Ethernet NIC and install it in your PC, or possibly you were able to use a USB interface you had, in order to use the new service.  OTOH many new PCs actually come with an Ethernet connection built in.  This is the connection that uses the jack that looks like a phone jack, but is bigger - RJ45.   ADSL modem service probably required you to run a little "connection software" that looks much like dialup connection you have been using all these years [it actually comes built-in to XP tho].  It actually is very similar - ppp protocols, except that it runs on top of the ethernet cable, resulting in the need for "pppoe." 

Now this is not too bad a thing if you had an analog modem and you were not on-line for many hours at a time.  Low bandwidth analog modems rarely connected to the Internet are not very interesting to the hackers and Internet terrorists.  Your PC ....may.... not have too many viruses, and be too riddled with spyware, but it probably has some.  If you were somewhat smart, you actually installed some firewall software, or you were using XP with ICF enabled, or you have XP SP2 installed.  If you were somewhat smart (again), you actually installed a NAT/router when you got that cable modem or ADSL connection.  Some ISPs actually distribute NAT/routers with their service now.  Most cable modem service providers DO NOT!  Cable modem or ADSL service is a high bandwidth service, and tends to be always on-line and susceptible to hackers and Internet terrorists.

The important distinction in using a NAT/router is that the NAT/router actually gets to face the cold cruel world of the Internet, and it is the one which takes the actual Internet IP address.  You are protected behind the NAT/router with a private IP address which the hackers and Internet terrorists cannot see directly.  This is a MUCH preferred situation.  When you combine this with the other safe computing techniques, there is actually a chance that your PC will be safe and you will not become an Internet terrorist [Did I scare you there?  I hope so - unsafe/unsecured PCs are actually putting the Internet at risk!! the hackers and Internet terrorists are routinely trying to get in your front door -the IP address-  in order to turn your PC into a terrorist....] 

An Important thing to note is that both your PC and the NAT/Router have a private IP address, and this particular address is not known worldwide, like the Internet IP address.  The private IP address of the NAT/Router will be called the "Gateway" address, because that is the Gateway to the Internet for all your PCs, which are connected to the NAT/Router.

If you want to pursue this information a little further, take a little side trip here, and then come back.  I reveal some good troubleshooting techniques you can use in your network.

Another important thing to note is that all these connections [except the Internet connection - that will be coax or phone line] will be done by using Ethernet cable - RJ45 cables.  This is a high speed capable wire, running at either 10 Mb/s or 100 Mb/s [don't worry if you don't understand that - it is just a LOT faster than the analog modem connection].  The NAT/Router may actually come with a few of these, and you may also have to purchase a few at your local RADIO SHACK, or your local computer store.  Also note that we have given up on the old analog modem as the main Internet connection.  We have relegated it to the backup role, in case our main High speed Internet connection goes down.  In this case, just leave your old analog modem in place on your old PC.  If you still have your old ISP account you can still use it as a backup.  ADSL service usually comes with a backup account which you can use via dialup.  If you have cable modem, you may be out of luck!  Cable modem service rarely provides for a backup analog connection [that would require a phone line, and they don't want to encourage anybody to have phone lines.....], whereas ADSL modem usually does.  See this page for some info on all these options.

Note also that the NAT/router may be combined with the ADSL modem, as well as a "hub," or a "switch."  "Hub" or "switch" ports are the place where you plug in all your PCs on the LAN side.  If your NAT/router only has a single LAN connection, you will have to buy a separate hub or switch to connect up all your PCs.  See this page for some info on hubs/switches.

After connecting up all those wires, you should verify that the wires are connected correctly.  Normally there is a little LED associated with each end of an Ethernet RJ45 link, called a "link" light.  You must have the link light ON on each end of the cable, or you cannot go any further.  If you do not have a link light, make sure you do not have the cable plugged into the "uplink" port on the router/hub.  Move it, or change the switch that may be available to flip the port between normal and uplink.  Normal ports are "PC to hub/switch/router connections."  Uplink ports are PC to PC or hub to hub (switch/router to switch/router) connections.  This page has some info on the Ethernet cabling.  This page has info on hubs and switches.  This page has info on RJ45 connections. 

Please note that if you are doing wireless connections, there is also a "link" light associated with this connection as well, but of course you don't have to worry about the physical cabling.  Whenever I mention "ethernet" just substitute "air" if you are doing a wireless setup.

Once you have achieved a link light, we now need to verify that your PC has a private IP address, mentioned above.  Most PCs are setup to automatically obtain a private IP address from a server once you connect up the Ethernet cable correctly.  To verify that you have a private IP address, open a cmd prompt [start -> run "command" on Win98/ME or start->run "cmd" on NT4/Win2K/XP].  Type the command "ipconfig at the prompt and see if there is an IP Address listed.  If so, you are making good time.  If not, you have other problems which we will have to investigate!  Please note the "Default Gateway IP address."  This is the address of your NAT/router. 

What you will have to do to setup the NAT/Router is to start your browser [that is Internet Explorer for most of you], and enter the IP address of the NAT/Router [the Gateway....] into the address field of the browser [something like "" or just ""].  Follow the instructions for your specific NAT/Router.  For cable modem service, you will have to most likely setup "acquire IP address automatically" on the WAN side.  The "WAN" side is the Internet side of your NAT/router, and the "LAN" side is the PC side.  For ADSL service, you will most likely setup "pppoe" service, and you will have to enter your username and password for your ISP.  This is setup just like your old dialup service, except here it is performed over the ADSL line.  Your PCs must be set for "acquire IP address automatically" so that they will acquire a private IP address from the NAT/router.  For the more technically inclined, you can certainly setup "static" IP addresses as well.  In order to configure the NAT/router for proper information, you will have to enter that address into the address field of your browser.  Follow the instructions for your particular NAT/router.  For ADSL, you typically enter your username/password here to initiate the pppoe client which logs into your ISP.  For cable modem service, the setting is normally "obtain IP address automatically."  This page has a lot of information on NAT/routers.

OK, that was quick.  You're probably itching to do wireless, or if you are like most people these days, you are probably doing wireless first.  Yikes, this is scary.  You people really scare me.  First of all, you should complete the "Basic Wireless Networking Course," another new addition to my site.   And be sure to visit this page to see a much safer [I didn't say completely secure - note!] way to install your wireless, especially if you already have a wired network.  This may be worth doing even if you don't already have a wired network.  If your secondborn or thirdborn above is actually a wireless NAT/Router, then the above descriptions still apply, but just replace the Ethernet connections with air!

Congratulations.  You have now graduated.  Send me an email if you want a certificate of completion! 

You don't even need to send me any fees.  You can now graduate to the next level of networking, starting here with basic wireless, and then here and here and then when you feel like battling Microsoft, go  here.  And then you should delve into the TCP/IP information on this web site.


Copyright John D Loop Wednesday October 26, 2005