I've just installed Fedora 14 in VirtualBox and got it up and running in a window on my Windows 7 host.
Its IP is 10.0.2.15 with subnet 255.255.255.0 (ifconfig). The Windows 7 VirtualBox's IP was a bit weird, so I changed it to 10.0.2.20 on the same subnet.
When I then try to open Fedora's IP in Chrome on the Windows 7 VirtualBox host, it can't find the server. Trying 127.0.0.1 on the Fedora box works 100%.
Pinging the server results in 50% loss, so it does seem like "it's there".
Any ideas what might be wrong?