Internet Connection sharing problem

[wintomato]

my brother has an xp pc connected via to the internet via broadband, and connected to that via a wireless netowrk connection is a laptop. They fileshare no problem, but we are having problems with getting the main pc to share it's internet connection.
When i go into the properties of the internet connection and ask it to share the connection, i get this message..
Cannot enable shared access.
Error 799: Internet connection sharing (ICS) cannot be enabled due to an IP address conflicton the network. ICS requires the host to be configured to use 192.168.0.1. Please ensure that no other client on the network is configured to use 192.168.0.1

I looked at the ipconfig in msdos and it says that the default gateway is using this ip address.
Problem is I don't really understand all the ip addressing, so don't really know what i have to do to free up this ip address and be able to share the connection.
can anyone help? They are both xp machines.
thanks

[glc]

You share the connection TO the wireless connection, not back to the same connection that the broadband modem is connected to.

Have you tried running the XP networking wizard, choosing the appropriate scenario?

[wintomato]

thanks glc.
Yes, i have tried the wizard and it gives me the same error in the wizrd, telling me that it can't do it as something else is using the ip address 192.168.0.1
The wireless hub is netgear, which I believe uses that address (?)
do i need to manually assign ip addresses? I am in the process of doing that but not having much luck

[wintomato]

I am getting errors 799 and 765 which both point towards something else using the ip address that it needs to do ICS

[glc]

Wireless hub? Could you please describe your topology a bit better, along with model numbers of appropriate components? If the Netgear is a ROUTER you do NOT use ICS.

[wintomato]

ok, yes, sorry, lack of details.
Well, the main pc connects to the internet through it's own broadband connection: a standard issue British Telecom Alcatel Speedtouch USB adsl modem.
The main pc has a wireless network card: Netgear WG311 802 11g Wireless PCI adapter.
The laptop also has a wirless netowrk card : Netgear WG511 54 mbps wireless PC card.
They both connect to each other through a Netgear Wireless Router MR814v2.

On this router there is a cat5 socket labelled internet, but my brother does not use this, as his modem is usb, so his modem connects directly to the main pc and not from the router.

There is no problem with file sharing.
Both computers use XP home edition 5.1 sp1

In the main pc's network connections there is the broadband dial up connection, the "Local Area connection" but this is "unplugged", the Wireless network connection and a 1394 connection. All are set to assign IP automatically

On the laptop there are the same, except obviously no broadband connection.

I have tried to assign different IPs to the wireless card but to no avail, and I have tried to assign a different defauilt gateway, but this doesn't work, probably for good reason, but i don't understand enough about IP addressing.

I guess an easy solution would be to buy an adsl modem that connect directly to the router, but my bro wants to avoid this.

thanks

[glc]

The router is your problem, it's assigning the lan-side IP addresses and ICS won't co-exist with it. Remove it and set up the 2 wireless cards in "ad hoc" (workgroup) mode and let them talk directly to each other - this will be exactly like using wired nics with a crossover or simple hub. If this is not an option, you might be able to fool the system by disabling the DHCP server in the router and changing its IP address to some other address in the subnet (like 192.168.0.254). ICS does *require* the lan-side nic in the host box be 192.168.0.1 and it becomes the DHCP server for the network - and only one DHCP server is allowed on a network segment.

Keep the router around for when you get an Ethernet ADSL modem (which you really should consider eventually).

Note - isn't that router just a "B" router? If so, you will get a lot faster LAN performance using the two "G" cards in ad-hoc anyway, unless the signal strength is low.

[wintomato]

thanks glc. I think reason my bro fell into this situation is because he couldn't find an ethernet modem anywhere, he tried all the large well know 'pc' stores like PC World in the UK. I have since put him straight and recommended dslsource.co.uk an excellent company who are very helpful, and have recommended he get an ethernet modem from them as I just feel he will run into more problems eventully.
I assume you mentioned that the router is just a B router as he still has the local area connections in there. I have disabled them, and will get him to delete them as they are not needed.
disabling the DHCP sounds like a better idea to me... well at least one I can understand and relate to.
thanks for your help glc.