I have 4 Fedora Guest - 2 are 10 and 2 are 11. When they reboot ( new kernal or for testing options ) the network appears to be working in Linux but It cannot ping outside or be pinged from outside but it pings itself with no issues. I tried both virtual ethernet types with no differences.
But if I login as root and run service NetworkManager restart and wait 10 second it sometimes will work and i can ping outside - It sometimes takes 3 tries. I have 2 bridged ethernets, one that can see the outside world and one that can see my private computers.
Also there need instructions to state that if a new Linux Kernal is built, you have to reinstall the guest addition to get them to work after you reboot into the new kernal.