IP problem when using Internet Connection Sharing in Windows XP

My Windows XP (SP2) laptop connects to a wireless network, and I would like another laptop to connect to the internet through Internet Connection Sharing in Windows XP.

In the XP laptop's wireless network connection property, under advanced tab, I selected "allow other network users to connect through this computer's internet connection". Then there is an error: "Internet Connection Sharing cannot be enabled. A LAN connection is already configured with the IP address that is required for automatic IP addressing."

I googled a little, and someone said:

ICS wants to assign 192.168.0.1 to the LAN connection. It can't do that, because the wireless network is already using the 192.168.0.x IP address range. The Internet connection and the LAN must use different ranges.

To use ICS, change the wireless network to a different address range, such as 192.168.1.x.

If this is the solution, I wonder how to "change the wireless network to a different address range, such as 192.168.1.x."? Does it mean that I have configure the router or modem of the wireless network? How to do that without having access to the router or modem physically? I also don't have password to configure that router.

If this is not the solution or there may be other possibilities, for example without configuring the router of the current wireless network, please let me know as well. By the way, I have another router available if that may help.

Thanks and regards!

Tim

Posted 2011-05-08T16:25:04.317

Reputation: 12 647

2If I read that correctly, you'd have to change your WiFi router's network to 192.168.1.X, correct. You wouldn't need physical access, just enter your router's IP in a browser and change the settings there. – slhck – 2011-05-08T16:34:47.300

@slhck: Thanks! my internal ip is 192.168.0.103. What is my router's internal IP? – Tim – 2011-05-08T16:51:39.377

1@Tim In most cases, it's 192.168.0.1. If not: run ipconfig and you'll find your router's address under "gateway". – slhck – 2011-05-08T16:55:40.283

@slhck: Thanks! I don't have admin password to change its WiFi network. So I think this way seems impossible now. Is it possible to buid ICS without changing the router? – Tim – 2011-05-08T17:48:59.763

Couldn't you just use 192.168.1.x for the LAN? Or does ICS not let you specify the IP range? – user55325 – 2011-05-08T19:05:44.803

@Tim It involves bridging the adapters but I'm not too sure on the specifics here, sorry :( – slhck – 2011-05-08T19:18:47.297

The second laptop has no wireless card/adapter to connect to the router (such that ICS would not be needed)? – therube – 2011-05-08T19:20:20.820

@user55325: How shall I use 192.168.1.x for the LAN created by ICS? – Tim – 2011-05-08T21:13:02.427

@therube: the second laptop has wireless and wired cards. But for some unknown reason, it has lost wireless connection and only wired connection may be possible. I have asked for its wireless connection in a previous post here http://superuser.com/questions/280618/can-a-laptop-access-wireless-network-through-another-laptop.

– Tim – 2011-05-08T21:14:44.610

@slhck: Did you say bridging the adapters is another way? Could you point me to some nice description of this way? By the way, I have another router available and I know its password, if that may help. – Tim – 2011-05-08T21:23:41.330

@Tim I guess this explains it. I've done something like this years ago for sharing an internet connection over a Firewire interface.

– slhck – 2011-05-08T21:31:31.283

@slhck: (1) I connect the two laptops with a Ethernet cable, and then on the XP laptop, bridge the Wireless network and the LAN corresponding to the two connected laptops. It doesn't work. Did I do something wrong? BTW: my the other laptop is Ubuntu 10.10. (2) My actual problem is http://superuser.com/questions/277108/lost-wireless-connection-after-os-continuously-on-for-a-week. The only way I try now is to get around the problem by http://superuser.com/questions/280618/can-a-laptop-access-wireless-network-through-another-laptop, for which creating ICS is just the only way I know to solve it.

– Tim – 2011-05-08T22:08:30.063

I am not the admin of the wireless network, and it is unlikely the admin will change the router for me. So leave me few choices: find some way that does not require configuring the router, or learn how to hack the router which I don't know yet. – Tim – 2011-05-08T21:48:36.727

Ah, I understand. You should probably break down and buy the other laptop a wireless adapter if you don't have admin rights to any of the network equipment; it would most likely be the fastest solution. – goblinbox – 2011-05-08T21:53:00.737

My actual problem is http://superuser.com/questions/277108/lost-wireless-connection-after-os-continuously-on-for-a-week. The only way I try now is to get around the problem by http://superuser.com/questions/280618/can-a-laptop-access-wireless-network-through-another-laptop, for which creating ICS is just the only way I know to solve it, but it looks like impossible without configuring the router.

– Tim – 2011-05-08T22:00:55.760

So if you can't change the IP range on your local DHCP server, why don't you change the range in ICS instead? The instructions for doing so are at the MS kb. – goblinbox – 2011-05-08T22:08:56.023

Thanks! Where are the instructions for change the range in ICS? – Tim – 2011-05-08T22:38:08.563

Thanks! If I change my ICS network IP to be 192.168.1.x, what should the subnet mask be like and why? – Tim – 2011-05-08T23:00:26.033

1Subnet should be the default, which will be 255.255.255.0. Because it's a class C network. – goblinbox – 2011-05-09T04:29:31.323

IP problem when using Internet Connection Sharing in Windows XP

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