I have a 2nd generation iPod Touch running OS 4 that I (usually) leave powered on 24x7. What I notice that I am unable to go online - I cannot check my email, browse the web, etc. My guess is that my wireless router's DHCP tables have recycled (or whatever the right word is) and that the iPod Touch needs to renew its IP address.
If I go to the iPod Touch's Settings it lists my network and the DHCP-granted IP address, DNS settings, and so forth. If I try to renew the lease the existing settings are erased and the iPod thinks for a while before bringing up a new IP address. However, this new one starts with 169.254 (or something like that) when it should start with 192.168. Needless to say, the connectivity problems persist.
The only way I can get back online is to power down the iPod Touch then power it back on, which takes upwards of a minute. Is this a known problem with the iPod Touch? Is it an issue with my router? Am I stuck rebooting the iPod Touch when this situation unfolds?