I'm on Snow Leopard and when I put the machine to sleep and then wake it up, I often find that it won't connect to my home wifi network any more. Thing is, I can see the wifi network, but when I try to select it to connect I get prompted for a password. When I enter the password it thinks for a bit and then tells me it can't authenticate (it's definitely the right password!). Before the sleep I was connected fine. My home wifi network uses WPA2 and I have it set as my only preferred network and to reconnect automatically if it drops.
The problem is a bit sporadic. On occasions waking it from sleep (by pressing the space-bar on the keyboard) results in it automatically reconnecting to my home wireless network. I'd say this happens one time in about five.
To fix it I usually have to either: disable and re-enable the Mac mini's wireless adapter (occasionally works), re-boot my router (usually works) or reboot my Mac mini (always works).
EDIT: The router is a Netgear DG834G.
What's going on here?
EDIT: I've a feeling this is a router thing. Something like: putting the Mac to sleep doesn't inform the router in any way so that when the Mac wakes, the router is confused because another device is trying to use the same IP address (I specify a fixed address for my Mac). Does that sound likely?