Hello,

To allow (KVM) virtual machine guests running on a Fedora 16 host
connect to host services one could open system-config-firewall, define
"virbr0" and "vnet0" as trusted interfaces, and be done.

On Fedora 18, the firewall-config GUI does not provide any means to
work with network interfaces.  Moreover,

# firewall-cmd --zone=trusted --add-interface=virbr0
# firewall-cmd --zone=trusted --add-interface=vnet0

works, but only until the next host reboot, while

# firewall-cmd  --permanent --zone=trusted --add-interface=virbr0
# firewall-cmd  --permanent --zone=trusted --add-interface=vnet0

just brings up a man page (no error message???)
This is firewalld-0.2.12-1.fc18.src.rpm

Andrei

PS. I am aware of #882736, which reports that the patch to firewalld
allows to restore VM guest functionality by setting default zone to
"trusted".  That workaround is unsatisfactory because of its potential
to create security problems.