Adding Internet access to an existing network

Hi I was wondering if any of you clever people could give me some advice!

A friend of mine runs a small shop - he has three computers that are networked with an Ethernet switch. This is linked into the till system too. On one of his computers ( in the office) he has a speedtouch USB modem for broadband access which works fine ( so the office computer is connected to the network via Ethernet and to broadband using the USB modem).

He has now introduced a fourth computer into the office. This one doesn't really need to be connected to the network but it does need Internet access. I was wondering what would be the best way to do this? I did try replacing the speectouch USB modem with a wireless router and connecting the two office computers wirelessly but the Ethernet connection seemed to override the wireless one and there was no Internet access without disabling it. Could I just replace the Ethernet switch with a 4 port dsl modem router? Would I need to reconfigure the whole network?

Would appreciate any advice on this.

Thanks in advance.

Andrew

ideally you keep the till systems disconnected from internet access.

the wireless arrangement you suggest should work, but you need to remove the default gateway on the first machines ethernet connection.

Can't you just plug everything into the wireless ADSL router via cable? Do you actually need to use wireless at all?

In reply to a post by Footys:

A friend of mine runs a small shop - he has three computers that are networked with an Ethernet switch. This is linked into the till system too.

He has now introduced a fourth computer into the office.

Could I just replace the Ethernet switch with a 4 port dsl modem router?

Yes. If they work on ethernet already, why bother changing to wireless? 10m, even 20m patchleads are cheap on Amazon.

In reply to a post by Footys:

Would I need to reconfigure the whole network?

I guess you might find something like NETBEUI in place if it's a old network, what you need to use is TCP\IP, and set this up to use DHCP (getting an IP address automatically). The router will dish those out for you.

Install the router first and get that working on it's own. Then add the PCs one at a time, fixing any problems as you go. DON'T try and change them all at once.

Top tip - be prepared to install Antivirus and Firewall software to each machine - up to now they have been relatively protected by not being connected to the internet. They will also likely need to attach to Windows Update and hoover down a LOT of patches and service packs - another reason to only do one at a time. As it's a business, many of the free utilities are not really on, as they are only licenced for non-commercial use.

If your responsibility stops at making the network work, not a major task. It's probably a lot bigger if you also have to update the machines, install AV, and carry out the multitude of other tweaks and tidying up that are likely to be needed.

In reply to a post by ggremlin:

ideally you keep the till systems disconnected from internet access.

the wireless arrangement you suggest should work, but you need to remove the default gateway on the first machines ethernet connection.

Yes I should have mentioned this in my first post - he doesnt want the other two shop machines connected to the till system to have internet access. How exactly to I go about removing the gateway? I need the machine in the office to still be connected to the network and tills but also to have internet access.

Ideally I would like to leave the network alone as it is all working well and just replace the speedtouch usb modem. So I guess what I`m asking is how can I have the computer in the office connected to both the exisitng wired network and also the wirless network for internet access?

removing the default gateway is done by control panel / network settings/ tcpip
just set that blank.
however there is another complication if the wireless router is issuing addresses in the same range
what addresses does the network use at the moment, and what router is it?

and yes its entirely possible to have a computer on more than one network

Thanks so much for the help = I dont know that information off the top of my head. I`m going to call round tomorrow at the shop and have a little play around. I`ll post again when I find out the information.