Airport Problems

Hello,
So I've been having problems with Airport as of late. I own an iMac and a Macbook Pro. My iMac is connected to the internet through ethernet cable, and uses the "Internet Sharing" function to allow my Macbook Pro to have internet connection. This has worked fine for about a year now. I went home for the holidays (turned off my iMac, brought my Macbook pro with me, used wireless internet at home, etc). Since I've been back I can not get the "internet sharing" to work anymore. I have been at friends with my Macbook since i've been back, and the macbook pro connects fine, there. And if I plug in the ethernet cord to my laptop it also works. Also, the internet backs are full, but in the Airport part of Network (in the control panel), Status: On, but it says "Airport has a self-assigned IP address and may not be able to connect to the internet.". Any help would be appreciated. I've been searching online and can't seem to find a solution.
Thanks.

Reconfigure the iMac's internet sharing settings, delete the network on the MBP and you should be able to connect or renew the dhcp lease.

Does the internet work on your iMac?

What is doing the wireless network - the apple units will handle both your Macs no problem. If u are getting a self assigned IP have a look here http://www.mac-forums.com/forums/airport-networking-wireless-technology/184699-got-new-router-having-some-connection-problems.html a also think about setting both up with DNS numbers for your ISP especially the MBP as it will make roaming better. See here and here

Yes the internet works on my iMac, that is what I am using now. I can't seem to figure this out. I'm trying to figure out the DNS thing. Do i put the IP number of my imac onto my macbookpro DNS box in the airport settings?

You shouldn't have type in anything manually onto the MBP. DHCP will handle everything as it should. First turn off the internet sharing option on the iMac and restart it. Concurrently, delete the network from the MBP and let it discover the network again and input your security key. This is all it should take if working properly.

You seem like you know what you are doing, but just in case.
How to Share Your Internet Connection on a Mac | R.Zambrano

On Snow Leopard it happens automatically as it sometimes does on Leopard but in Tiger they usually need to be added manually. So it depends on OS it seems, but you can check to see if they are there.


Click for full size

I have found it improves roaming on laptops to have a location for home with the numbers showing up as above.

Collin Bl said:

On Snow Leopard it happens automatically as it sometimes does on Leopard but in Tiger they usually need to be added manually. So it depends on OS it seems, but you can check to see if they are there.


Click for full size

I have found it improves roaming on laptops to have a location for home with the numbers showing up as above.

Click to expand...

so I put those numbers in my macbook pro and it still doesn't work. Although the browsers (safari, firefox) do try to load longer (the wheels are turning), but eventually they say that I am not connected. And I have tried removing the network from my MBP, and changing the network on my iMac, and restarting, but still nothing.

The nameservers for your ISP can and most likely will be different thanthose in the picture above. Do not input those.

OK Lets go back to the start - have you checked that the modem or modem/router is set to DHCP and on Macs using Airport in their Sys Prefs/Network/Airport/Advanced/TCP/IP is set to - Configure IPv4: Using DHCP.
If you are not sure about this then post the model of the Modem or Modem/Router and we can try and find the settings page for you.

Yes, it is set to DHCP.
The modem is a Scientific Atlanta DPC2100 Series Cable Modem

I am not using a router (I use my iMac as a router by "internet sharing" but that's the problem, it isn't working.

Did you try everything suggested in post #5 above? Completely reset up your Internet Connection Sharing in OSX and zap the connection from Air Port on the MBP and start from scratch.

Ok I just trid it again, and it doesn't work. Now My internet on my iMac says its sharing, but my MBR doesn't even list my network as one that I can join (I live in highrise building, so there are many other networks listed). I manually typed in the name and password of my network, and it says "Connection Timeout", and does not work, all while my iMac says it is sharing the internet connection.

OMG so then i turned airport off and on again on my iMac and the network showed up on my MBP! AND IT WORKS!
Thank you all for the help! Very much appreciated!

Good to hear we can help!!!