Tech wizards, please help me with an ethernet switch problem.

Factual Questions
1

I have a computer and an Xbox 360 and until today in order to get online with one I had to transfer the single ethernet cable from the modem and plug it into whichever device I wanted to use and reboot the modem.

Today I bought a Dynex 10/100 Fast Ethernet Switch. I can plug the modem into it and the switch into the computer or the Xbox and get both online, but not at the same time.

If the computers connected to the internet I can see the Xbox on my Network Map, I know they’re talking because my computer just asked me if I wanted to set up a picture and video sharing program with my Xbox. I set my Xbox up to acquire its own automated address settings and it comes back with an IP and Subnet address but not a Gateway address which makes me believe the Switch recognizes it but won’t let it pass to the gateway.

I tried putting in the IP, Subnet, gateway and MAC settings manually but it didn’t work.

I called tech support and cruised the FAQ and Xbox message board clowns, but all to no avail.
I’d really appreciate any help.

2

A switch doesn’t allow multiple machines to connect at once. If your modem doesn’t have a built-in router you need to buy one.

3

Agreed. You need a router. Your network should be something like:



Modem --- Router --- Switch ---- Computer
                       |---------XBox

Note that many routers are themselves 4-port or 8-port switches.

4

Back to Best Buy. Thank you gentlemen.

5

Actually, a switch does allow multiple machines to connect at once – to each other.

What it can’t do, though, is either route traffic between networks or perform Network Address Translation, and you need both.

Your modem’s job is to assign a single IP address from your network provider to whatever device it’s attached to. This is what we’ll call your “public facing” IP address.

So before the switch came into your life, the modem was doing its job just fine… whichever device you attached to it, it would dutifully hand that device an IP address and let it send and receive traffic.

Now you’ve added a switch. This allows both your devices to see the modem (and each other) but since the modem hands out only one IP address, the other device is left in the cold, without a public facing IP address of its own.

Now, adding a router will solve part of your problem. The router has two different networks defined on it: a public facing network and an internal, private network.

So you’ll plug the router into the modem, and the router will get the public facing address. And then it will “route” that traffic to the private network side and back.

But there’s still a problem: you have only one public IP address. The moment you want more than one machine to work, you’ll be out of luck.

Routers solve this problem by automatically implementing a feature called “Network Address Translation,” or NAT. They assign a whole bunch of IP addresses to the private network, and basically keep track of each session going in and out. So as far as the outside world is concerned, you’re a single (very busy) IP address, even though behind the scenes, on your private network, there are ten different computers creating all that traffic.

Routers also simply the problem of keeping track of the private addresses by handing them out to a machine that asks for one, using a process called Dynamic Host Control Protocol, or DHCP. This eliminates the need to manually add an IP address and gateway information; the router can provide that to each of your internal machines.

6

The Straightdope - for not only an answer but an education. Thanks Bricker.

Router set up and everything works great.

Must say, finding a nonwireless router is a bitch.

7

You just get the wireless ones and shut off the wireless. Usually they cost about the same.

8

Here you go: http://www.amazon.com/Cisco-Linksys-EtherFast-Router-4-Port-Switch/dp/B00004SB92/ref=sr_1_13?ie=UTF8&s=electronics&qid=1277051236&sr=8-13

But, getting a wireless one is probably a better idea.

9

Yup, that’s what I got.