Airport has a self assigned IP and can't connect to the internet

Thats what i get when i want to share an internet connection from my mini, macbook and macbook unibody.

none of them give an internet signal out to the world, they used to, but i think the last software update changed things.

so, being that i have the same problem with 3 machines i can say for sure its not a hardware problem, tried manually assigning an ip address, changing the network channel to any of the options.

still im giving no internet to any device. Running snow leopard 10.6.5 on c2d intel machines.

please, help me, as im getting heavy complaints from other people who havent got internet access for days thanks to this.

thanks

To help, we're going to need to know a little more about your network setup. What exactly are you trying to do, what kind of router do you have? What machine is sharing the internet to the rest, etc.

Also, have you tried rebooting your modem and router?

Clear the network settings, use the little (-) icon to do this, reboot the router and set up as an entirely new connection starting with wired ethernet, and then setting up wireless.

i have no router. i just have one mac connected via ethernet to the internet, and i want that machine to share internet via airport / wifi to other devices such as a macbook or an ipod touch

this worked wonders for a while, then stopped working, then worked again, then stopped. it seems it comes and goes as macOSX updates come and go.

i restarted the modem, cleared all network settings, tried to manually assign an ip, changed airport channels, none seemed to work.

thanks