My ibook won't connect to the internet. But it will connect to the LAN.

I have an ibook that won't connect to the internet. But it will connect to the LAN.

Connecting with ethernet doesn't help but if I connect directly to
dsl, bypassing the Linksys wifi router, then it works fine.

This is the error in the network status window:
"airport has a self-assigned IP address and may not be able to connect
to the internet"

I was able to upgrade the router firmware and the ibook itself to 10.3.6.
Neither upgrade helped.

SOME LINKS:
http://forums.macosxhints.com/archive/index.php/t-24540.html


I have only tried step 7, not all this crazy stuff:
 
>  How I solved it:
> 
>  1) Shut down the laptop.
>  2) Remove battery.
>  3) Remove airport card.
>  4) Reinstall battery.
>  5) Start up the machine.
>  6) Log in as root. (You could also log in as any admin, but you will 
> have to
> authenticate.)
>  7) Delete your com.apple.airport.preferences.plist found in 
> /Library/Preferences/SystemConfiguration/
>  8) Use Onyx (or similar) to delete all caches, system caches, virtual 
> ram caches etc.
>  9) Shut down the machine.
>  10) Remove battery.
>  11) Reinstall airport card, making sure it is seated properly.
>  12) Reinstall battery.


Intro to terms:
http://docs.info.apple.com/article.html?artnum=18237


Also interesting:
> 
> If a wireless laptop receives a self-assigned IP address, it tells you 
> nothing more than the fact either (a) it was unsuccessful at 
> establishing a wireless connection with a Base Station or (b) it was 
> unsuccessful at communicating with the network's DHCP server. The 
> reasons for this could be as much the fault of the laptop as one of
the Base Stations.
> 
> How many clients do you think could be connecting to one Base Station 
> at a time given your current setup? There is a maximum of 50 clients 
> permitted per Base Station, but it is possible that as you get close 
> to that number the full bandwidth of one Base Station might be almost 
> fully utilized - thus preventing one individual laptop from 
> establishing communication with the DHCP server on your network
before its connection times out.


thanx in advnce,

You need to make sure that the DHCP server that provides your ibook
with an IP address is also providing a Gateway IP address that is the
router, and also provides appropriate DNS servers, which may not have
been configured in the router (you should get DNS IP's from your ISP).

If you can connect to the LAN, you should be able to also web browse
to your IP address of your router, usually http://192.168.1.1 ... If
you can do that, you're definitely communicating with the LAN. Check
your ibook's IP configuration to make certain you have a gateway of
the same IP address. If you have that, you should be able to try to
ping an outside email IP address. (If you don't know of an IP address,
you can ping some famous website and get their IP). If you can ping an
IP address, then try to ping a URL. If you can ping the IP, but not
the URL, you have a DNS problem. Usually, you can configure your
router to provide the DNS for you, or you might be able to put your
ISP's DNS servers directly on your ibook and let the router's NAT do
its thing.

On a completely unrelated note, you may be having problems with your
DSL /Linksys connection. DSL may require setting up the router to
authenticate with your ISP via PPPOE on demand.

Furthermore, your ISP might be forcing your DSL modem to be monogamous
to one PC's MAC address. If that's the case, you'll need to masquerade
your MAC address (a setting on Linksys.) Do NOT do this unless you
know you HAVE to.