Credits to Issue 11236 - android - DHCP client ignores lease time - Android - An Open Handset Alliance Project - Google Project Hosting A problem with Android 2.2 DHCP has been identified. It causes the tablet to attempt to use expired IP addresses, which will cause your router to ignore your tablet. It appears to relate to a suspect implementation of the sleep protocol in 2.2. Basically, if your device goes to sleep its 'clock' that keeps track of the IP address lease stops, so when it wakes up it thinks the lease is still valid when, in fact, it has expired. There is not yet a complete fix (and there may never be one!) but it has been suggested that changing the wifi sleep policy will fix 80% odd of the problems. Go to menu/settings/wireless & networks/wi-fi settings/menu/advanced/wifi sleep policy/ and select 'when the screen turns off' If you have any installed apps that modify the wifi sleep policy or the way android turns wifi on and off this fix wont work! An example would be an application designed to keep your device's Wi-Fi interface always turned on. Another would be an application configured to turn on your device's Wi-Fi interface based on certain conditions (for example, location, time of day, or battery charge). While I have not personally had the problem of not being able to connect to my home network, probably because my android tablet will usually be assigned the same IP address anyway (most of the nodes on my home network are fixed addresses and only mobile devices are DHCP). I have however seen bogus MAC addresses appearing in the connected devices list of my router and I suspect this is all part of the DHCP bug that Google seem reticent to fix.