Why you can have an "Excellent" wireless connection, but no Internet!

This is the first of many articles regarding basic networking concepts and troubleshooting.

One of the most common misconceptions is that when your wireless connection says "Excellent", that somehow has something to do with your connection to the Internet.

The wireless networking indicator only indicates how good your connection is to the wireless router, which really has nothing to do whether or not you are on the Internet - in fact, you could set up a wireless router in the middle of the woods with no Internet connection for miles (well, assuming you had power), and your computer would still think the connection is "Excellent" as long as it is close to the wireless router.

The reason for this is because your wireless router actually has TWO "networks" - the LAN (local area network) and the WAN (wide area network, or the Internet).  The LAN network is typically comprised of both wireless and wired devices (hence the 4 LAN ports on most routers).  The WAN network is typically comprised of just one wired port, where most likely you have your cable modem or dsl modem plugged into (which could be routers themselves, but for this example we'll assume they are just access devices).

When you are connected to your wireless router with "Excellent" or "Very Good" or what have you, your computer is telling you that a) you have a good signal, and b) your computer has successfully obtained an IP address from your router.  However, the IP address you've obtained is a "private" IP on the LAN network of your router (it isn't a "real" or "public" Internet address) - in other words, you aren't necessarily on the Internet.

Now the router has to do its job, which is to route the information from its LAN network to its WAN network (the Internet), which includes translating and mapping your private IP address into an Internet IP address (usually you get one Internet IP address assigned by your ISP).

So, there are various scenarios where your connection to the LAN network could be great but you aren't getting on the Internet, here are the most common:
Your dsl modem or cable modem has "locked up" - try rebooting your cable/dsl modem by unplugging the power from it, waiting 10 seconds, and then plugging it back in.
Your router has "locked up" - the router actually has a little computer inside of it, and it can crash like any other computer - try unplugging the power from your router, waiting 10 seconds, and then plugging it back in.
Your cable or DSL service is out - call your service provider.
You have a hardware problem - either your router or your cable/dsl model could be "dead" - try bypassing the router to narrow the problem down.

Why does a router make things so "complicated" - well, your ISP typically only gives you one Internet IP address, so the router allows you to share that one IP with several computers (by virtue of the separate LAN network and something called NAT, or Network Address Translation).  In addition, having your home computers on the LAN network of your router and not "open" on the Internet provides a nice layer of security - basically it is a very simple firewall.  That is why some applications that require direct inbound access to your computer don't always work when you are behind a router (without configuring your router at least).

Anyway, that's it for our first networking "lesson" - hope this information proves useful.

Visit http://www.smileyfacepc.com for help once you are up and running on the Internet.