I boot up
launch web browser (konqueror)
works fine, get IP address via wireless or LAN
load google.com, ping anything, etc just fine
let sit idle for less than a minute,
reload google & "get page not found", ping nothing except localhost & local ip address
network connection appears fine

release & renew IP address (dhclient -r then dhcclient)
get same or different ipaddress and can load any web page ping anything
wait one minute & can't

This happens at home (linksys wireless router dhcp to mindspring<puke> dsl modem), at office (windows network) , regardless of wireless or wired connection. All windows connections work fine.
I'm using fedora 8, I don't have this problem on Fedora 5.

any thoughts sugestions?

I'm pretty much a Linux newbie.
Searched for:
keep network connection in Fedora 8
loosing network connection in Fedora 8
loosing network connection
and couldn't find anything related.
working on this for days so far.

First thing I'd do is check syslog for details that might be related to this. Then check if your network settings match the network you're on: if you advertise things you shouldn't you might confuse DHCP. Next I'd check if there's anything else wrong with getting a lease. For that you could check the default lease file (/var/lib/dhcpd/dhclient.leases) for details and if it doesn't show things make dhclient log verbose one of the man pages ('rpm -ql dhclient|grep man/') should show how.