Alright, my situation is this. I’m renting a house with 3 other people this year for college and we decided to go with cable modems for our internet access. I was put in charge of getting it, which is nice because I know nothing about it. First, because we don’t have a cable outlet in ever room we’re going to have to buy a router and run cables to the rooms right? Second, the good people that provide the service have a standard rate, plus an extra charge for each additional IP. I’m under the impression that normaly each computer needs its own IP, but I don’t know if that’s still true with a router. So basically my question is do I need multiple IPs if I have a router or can I get away with just one? Also if you know anything about the performace of wireless routers compared to wired ones that information will be very helpful because I’m very confused. Thanks for your help
I have daughters in college running pretty much this same setup.
Normally, you’d just get one cable modem, then attach a router to it that connects all of your computers to the Internet. Technically, you’ll only have one (shared) IP address to the Internet, but that’s nothing to worry about because the router takes care of all of the details for you.
These days, routers using wireless technology in addition to wired connections only cost a few more dollars than their non-wireless counterparts, so I’d definitely recommend doing that rather than running wires everywhere.
Given that you have no expertise in these things, I’d recommend finding a (local) friend that does and can set this up for you. Otherwise, I’d recommend letting the cable company handle the whole thing.
You basically have two choices. Pay your cable company for additional IPs or buy a router (probably a wireless router) and then you have one IP externally and the router assigns each machine connected its own internal IP that it manages using port numbers (I don’t recall all the details). The latter involves an initial expenditure that the former does not, but has the additional advantage that the router will include (AFAIK all routers do include) a hardware filrewall. There are also certain disadvantages, although I am not sure if that isn’t because I have an early version of the router, but certain things do not run smoothly, especially the telnet connection I use to my office computer. And VPN (virtual private network) to my office computer is hopelessly slow. The router company (D-Link) ignores my queries.
Here’s how it works:
ISP gives you an Internet connection. This connection comes in to your cable modem. A wire from your cable modem then goes into your computer. You computer is connected online with the IP address provided by the ISP.
Here’s how you want it to work:
ISP gives you an Internet connection. This connection comes in to your cable modem. A wire from your cable modem then goes into your router. The router is connected online with the IP address provided by the ISP. 3 cables come out of your router and go into each of the PCs. The router assigns each one of them an internal IP address. So, for all practical purposes, you don’t need an additional IP address from your ISP.
If you get a wireless router, you won’t need the cables to each of the computers. The IP assignment will still work in the same way. I am quite happy with the range of a wireless router. You will need 1 wireless card for each of your computers. As long as you’re within a reasonable range the wireless connection is excellent. And a whole lot more convenient, if a bit more expensive.
Thank you all for your helpful, and extremely fast, knowledge. My housemates and I are very happy to hear we won’t have to pay for the additional IPs. Cheers
I am computer illiterate, but was able to install modem and router in my house (basement and upstairs) with little trouble. Here’s the “dummy’s version” of the installation: Cablewire goes into modem. Another wire connects modem to router. Wires come out of router to connect to each computer.
First, I had cable company company come to my house to install the cable wire. Running the cablewires was free, but they charged $35 for drilling the first hole in the wall and $5 for each additional hole (for getting wires in each room).
Next, I installed on both computers an ethernet card (which I think is a card that slips into your computer and literally allows you to connect the cable into the computer – it looks like a slot for a telephonejack, only it’s made for cable). It was merely a matter of slipping the card into a slot in the computer and running a self-installation disk.
Next, I connected the cablewire into the modem, connected a cablewire from the modem to a router, and connected 2 (in your case 3) cablewires from router and ran one into each computer.
I designated one computer the Primary Computer that would be given the IP address. (In your case, you might want to designate your computer if the bill comes in your name). Multiple wires come out of the router. One slot in the router is for the primary computer. The remaning slots are for the other computers. If your computer is designated the primary computer, then make sure that your computer is connected to the wire coming out of the primary slot on the router.
In the primary computer, I ran the self-installation disk that I received from the cable company. I had trouble with the cable company’s disk – it wasn’t installing the program – so I called the cable company and they were able to “ping” me from a remote location (which I think means they installed the program remotely). I was not charged for this. Intially, I thought the problem may have arose b/c I tried to install the router, but I honestly think the problem may have been with the disk. I did not tell the cable company about the router when I called.
I then ran the self-installation disk for the router on the primary computer. No problem.
I then ran the self-installation disk for the router on the second computer. No problem. I did not need to re-install the cable company’s disk in the second computer.
And, that’s it. Both computers could work at the same time. My roommate used the one downstairs and I used the one upstairs.
Good luck~
Routers are more expensive than hubs and switches, and wireless routers/NICs are even more expensive. If you’re willing to pay the per-IP charge, you can get by with a hub or switch instead of a router, then just connect the cable modem and the PCs to the switch.
This will give you a more direct connection to the internet, which can help with file sharing, DCC file transfers on IRC, AIM direct connections, and other situations where your computer needs to accept connections from outside. OTOH, it also makes you more vulnerable to attacks for precisely the same reason.
Use this product it is great and easy to use. It is $40 from amazon.
http://www.linksys.com/Products/product.asp?grid=34&scid=29&prid=20
I’m an 68 year old man. About three years ago I installed my cable internet. I already had cable TV so all I needed was a splitter, the cable company furnished the modem, splitter and extra cable. I furnished the labor. I hooked it up, turned it on and came on-line.
About a year later I bought a new Dell computer, my wife wanted the old IBM Aptiva so I purchased a router. Ran router cable from the router (75 ft. under the house) to her computer at the other end of the house. Hooked it all up, turned on the router, out of the box from Walmart… both computers worked like a charm.
I had never touched a computer mouse until my first computer in 1997. What I’m saying… you young bright men will have no problem if I can do it. 
I have a cable modem going into a router, and then 2 cables going to each PC. The only problem I recall is directionality of the cables - I think there’s cables that cross over and switch signals and some that don’t, maybe someone can clear this up (or ask the store helpers). I did try a hub at first, but had zero luck - for some reason only one computer was able to access the internet at a time.
A hub will not be able to support 2 computers simultaneously on the 'net. That’s what a router is for. The only way a hub can do that is if the ISP offers you 2 IP addresses.
Here’s a neat diagram of possible configs:
http://www.pcnineoneone.com/howto/hmnetwk1.html
Cross-over cables are generally used to link up 2 hubs together, or a router to a hub, or a cable modem to a router, etc. A straight through cable is used from the computer to the router or hub. A cross-over cable is the cheapest way to create a LAN of 2 PCs. Just connect the cross-over cable between the 2 PCs. A straight through cable will not be able to do this.
Bob55: Crossover cables switch the send and recieve lines, regular cables don’t. Crossover cables are for connecting two hubs, or for connecting two computers with no other hardware. If you don’t know what it’s for, you probably don’t need it.
Also, if the cable company is only giving you one IP, then the first computer on the hub to ask for it is gonna work, and the other is SOL. That’s why routers are so popular these days.
Some notes for sharing one connection over a router:
Good: A router keeps loads of dumb attacks away from your machines.
Bad(ish): Most multiplayer games don’t work if you’re hosting behind a router, at least not without more work than you’re capable of right now.
But for surfing and stuff, it’s the way to go. 
If you’re going to get a wireless router, be advised…the PCI card that recieves the signal from the router will be located in the BACK of your computer…most likely facing a wall or some other structure. Therefore its quite essential for you to plan the placement of your router in such a way that it gets maximum exposure to the three computers in the household. IE, central location between them would be most desireable. Also something particularly high.