I've installed CentOS 5 inside KVN on FC12. I've setup a bridged network that works fine. I can ping the virtualized host from any of my other computers and the other way as well. I can also access apache on the virtualized host from other computers on the LAN. I also have no problems doing 'yum update'
However, when I try to access any UDP service eg. DNS that resides outside my LAN I never get a reply. eg.
nslookup google.com - <known nameserver>. When I try this from the host OS, the exact same command I get a reply.
I've tried sniffing the traffic by port mirroring the port that goes to the ADSL modem router (DG834G Netgear) in both directions. The DNS request travels out to the internet but I dont get a reply. Just casually comparing the packet sent by the host and the virtual OS I dont notice any significant differences. Then again I'm not sure what to be looking for.
iptables host FORWARD has one rule (guest iptables is off):
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 PHYSDEV match --physdev-is-bridged
Network is simple, one L2 managed switch and everything connected to it.
I've also tried creating a port forwarding rule for various UDP services and testing them but no luck there either.
The host and guest are configured using static IPs but there is a DHCP entry for the same ip/mac on the router.
It appears to be the DSL modem router. I just swapped out the current one for a one on loan and it works just fine. I have absolutely no idea why, I just used the default factory settings on the loaner. Any idea what might be the cause? I've tried changing various settings etc. but I'm not sure what specifically it might be.