I'm a networking novice so I need some help with something that should be easy.

I've moved into a situation where I need to share a 4Mbit cable modem connection between my Debian Sarge and an old Win XP Home box. Would this be best done with a switch/router/hub/repeater?

I'm thinking:
- the two boxes don't need to be aware of each other
- prefer wired to avoid signal problems with wireless[1]
- no hardware firewall to make things simpler and it seems to complicate p2p

Anything I buy would certainly work with the Windows so reccomendations of models which are linux friendly would be great.

Thanks for help!

[1] plus neither computer is wireless capable or do all the wireless routers I see come with something that plugs into the ethernet ports?

Most firewall/modem/routers will work with Linux. Since I don't know what a cable modem connection is, I can't really recommend you a model. However, any router made by a reputable company will have specs up on their webpage. So long as it has more than one ethernet port and a web-based configuration tool you shouldn't have any trouble. If possible I recommend getting one that incorporates a hardware firewall. If you want to operate P2P on more than one computer you will have to set up port-forwarding whatever kind of router you get, and one with a built in firewall will offer you more security.

One other possibility is if you happen to have a spare old computer about, you could stick a PCI modem and a couple of ethernet NICs into it, and run it as a router using something like Smoothwall.

Thanks for your feedback. "Cable modem connection" meant my isp is a cable company (as opposed to a telco) and I want to share internet through the cable modem. Both computers have software firewalls working fine. That's why I didn't want one in the hardware. I'm trying to minimize complexity. Same thing with port forwarding. Would a switch/hub allow me to avoid port forwarding? (Reading the wikipedia entries on switches and routers didn't clear up for me the differences and pros and cons of each.)

I connect a couple of linux desktops and a xp machine thru a netgear router using wire. Plus its has wireless to so when the kids come home with their laptops they can use the internet on their own machines. Setup was easy. Compatability is not a problem since TCP is used by the modem, router and all the computers to talk to each other. Cost was less that $100 for the router and a couple of network cards at Fry's.

Well, I still don't understand what a cable modem connection is. We don't have the distinction here in the UK as far as I know.

What would you connect a switch/hub to? Remember, from outside your home network there is only one IP address visible. Internally on the network computers have separate IP addresses, but these are not visible from the outside. Suppose someone on a P2P network wants to make a connection to one of your computers. How does your router know which computer to forward the data to? You will have to enable port forwarding, so that connections will be forwarded to the correct computer inside the network, regardless of whether you have a hardware firewall or not. That being the case, having a hardware firewall will increase security but won't increase complexity.

I have to disagree with louieb on a point: if you don't have any wireless hardware, avoid getting a wireless router. It's just another way people can get into your network. Even leaving aside malicious breakins, you might not be too pleased to find your neighbours were using your bandwidth for free...

Many cable ISPs only provide one dynamic IP address with their default service. If this is the case then a hub/switch will not work and you will need to use a hardware router or configure one of the PCs as a router.

You only need to enable forwarding if you want to access a PC from the internet.

The type of modem (modulator/demodulator) is dependent on the type of internet service your using. For most, home internet access is either dial-up, cable or DSL. With cable the internet service is sent over the same wires(coax) as your cable TV service.

Sorry, I didn't sign up for this isp so I'm not totally familiar with all services it provides. I found out that it provides 3 dynamic ips which suggests to me a switch would be fine and a router isn't necessary.

So if each box makes its own dhcp request, is that the right topology? If so, all I need know is to figure out how to change Debian over from pppoe adsl to cable.

What you have will work.

If in the future you want to share files between the computers via samba then I suggest using a hardware router due to smb not being secure. You can always use ssh instead.

Who is your cable providor?