Description of problem:
i've been using a virtual machine as an internet gateway since FC13. on the virtual machine, eth0 is bridged to eth0 of the host, and eth1 is from the default virtual network (NAT) of libvirt. the virtual machine thus provides internet connection to the host as shown below:

{INTERNET} <---> [eth0-VM-eth1] <---> [virbr0-Host]

this configuration works fine on FC13 and FC14. however, after i installed a fresh FC15 and setup virtualization the exact same way i did before on FC13 and FC14, the host cannot obtain internet connection from the virtual machine.

i actually have another virtual machine, which also obtains its internet connection from the aforementioned virtual machine (also via NAT). there is no problem on the second virtual machine getting internet connection from the first virtual machine though. 

Version-Release number of selected component (if applicable):


How reproducible:
Always.


Steps to Reproduce:
1.
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Actual results:
Cannot resolve DNS.


Expected results:
Can resolve DNS.


Additional info:
please see more details and test results on http://forums.fedoraforum.org/showthread.php?t=265829