Self Assigned IP - Fixed, but help still needed, please

I'll add a bit of a back story first which I hope will help people understand my issue, but also hopefully lead people with a self-assigned IP issue to a fix (link is within the post)

I’m on on an iMac 20″ Mid 2007. I recently updated to OSX Lion after having wifi connection issues in Leopard. I used to randomly get kicked off my wifi and given a self assigned IP. With Leopard, the issue was fixed by applying a manual IP, router address etc and restarting. The issue would return months later, but I got over it after a few tantrums.

Then as soon as I updated to Snow Leopard, I instantly had no internet access and I could only upgrade to Lion if I downloaded system updates. So after a few hours of searching, I toggled my internet sharing ‘on & off’ and that was enough for that fix.

But then I upgraded to Lion and again, no internet. And nothing worked for me at all, every fix on the internet I tried failed. If my airport ever managed to connect to my router I would get a self assigned IP. Or it would say it was connected but there was no internet. So I hunted for hours and eventually found this:

Now, here is a fix for anyone who is having the same issue. I hope it works for you!

http://www.davidpierron.com/index.php/archives/2009/04/13/289/

This did work for me. The fix is to flush your ipfw through terminal, and it worked for me instantly.

However, I now have another issue that I really hope people can help me with. It's not as annoying as the above, but my god it's still very annoying!

Here are some bullets to show the tedious routine I have to go through in order to connect to the internet via my airport.

• I turn on my mac and my it tries to connect to my router automatically. But after a minute of trying, it says it can’t connect.

• I select my router manually from the list and have to enter my password manually, even though it is already saved in my Keychain.

• It then connects and says, ‘Connected but no internet’, so I leave it for two minutes and throw things around the room.

• After those 2 minutes it connects to the internet. But no, I can’t browse the web as the browser says 'DNS look up failure'.

• So I open terminal, enter 'sudo ipfw flush' to flush my ipfw and BINGO, I’m online 5 minutes after logging on to my machine.

The router I am using was only issued to me 8 months ago by my new ISP here in the UK, it connects via WEP and has always been stable for every other device I have connected to it. But I am going to ring up my ISP and see if there is a new router I can get.

If anyone - ESPECIALLY APPLE who seem to be shying away from admitting there has ever been an airport wifi issue - has any information to advise me, then please let me know.

Also if you are having a Self Assigned IP address issue and that fix above works, give the man some credit on his blog, and if you know him, give him a kiss from me!

Thanks