I have 64-bit ArchLinux based (3.3.8 kernel) home server.
It plays mythtv backend/file/VoIP server. It is also my gw/firewall to internet (2 nic, iptables fw).
fw is setup in "deny all" style (
-P INPUT DROP,
-P FORWARD DROP)
I also setup kvm on this machine. KVM networking is via vde with vde's tap0 bridged to eth0 (my LAN facing phy interface).
Network subnet is 192.168.1.0
kvm(.190)<-->vde(tap0)<->bridge(name=lan0; ip=.254)<->nic0(phy dev)
kvm works, I can bidirectionally communicate between kvm guest(.190) and host(.254) - but not with my LAN hosts!
Issue seems to be related to
-P FORWARD DROP rule in my firewall as not executing this rule allows to work all networking OK.
I have problem to understand why
-P FORWARD DROP causes issue.
From L3 perspective, kvm network interface is behind LAN nic (it is bridged to LAN nic) so on L3 level it should work.
It looks like
-P FORWARD DROP is blocking traffic from other LAN hosts.
thx in advance