Help Please: Share Ethernet Internet via Airport

Im trying to share my Internet that comes from my DSL modem with my brother via Airport, using Internet sharing.

We are both using MBPs with Leopard.

When I share the Internet via Airport, airport says m IP is 10.0.2.2 subnet mask is 255.255.255.0 and the router is 10.0.2.1.

When he connects though, his aiport IP address is a self-assigned one 169.254.223.216 and a subnet mask of 255.255.0.0. Of course this self-assigned IP will change from time to time as we unsuccessfully try to get the sharing working.

It seems that his computer is not getting a proper DHCP IP address from mine, nor connecting properly.

Can anyone suggest what to do? Right now we are stuck at only one computer being online at a time.

 

it's because you are using a modem, and you need to use a router to do that, because your computer doesn't act like one.. those IP's are normal, don't worry about them, but that thing that you can't be online with 2 computers at the same time is.. rare

 

Can someone who has a clue as to what Im talking about suggest a solution?

 

This is possible. I had my iMac and MBP configured this way with Tiger when my previous wireless router died.

First I disabled AirPort, File Sharing and the Firewall on both Macs. Then I checked the computer directly connected to the Modem via Ethernet to make sure it was active. I just opened Safari and went to www.Google.com. Then I set up Internet Sharing. System Preferences>Sharing, checked the Internet Sharing tick-box. Selected From Ethernet and To AirPort. Clicked AirPort Options and entered the Network Name and enabled only 40-bit WEP encryption. Then Turn AirPort back On for both Macs and you should be able to connect to share the internet connection from one Mac to another. You may need to manually select the Network on your Shared computer.

I watched a nice video on CNET awhile ago that described the process, Make Your Laptop A Hot Spot. The video is from 7/17/2007 so the guy is specifically describing the process on Tiger.

 

I did that once too but it was very easy. I plugged in the ethernet, then went to the Airport symbol in the menu bar and selected "Create a Network".

Boom I had a WiFi network that my PC was able to connect to just fine. DHCP worked too.

If you don't get a DHCP address, did you try connecting with a manual address? Connect to the wireless network, then go to network preferences, and change to manual, enter
10.0.2.100 for IP address
and
10.0.2.1 for router address

And the subnet of course: 255.255.255.0

And see if that works. It should.

Don't bother with security settings until you get it to work. You can do that once things are working, but get the unsecured network working first.