Forwarding w/o promisc on 6.4

[Jon Otterholm]

Hi.

I have a router running 6.4R that does not forward packets if I disable
PROMISC on the interface.
Hardware is a Dell PE with two Intel 82541EI chipsets (if_em). I have a
number (~100) of vlan-interfaces on em0. Everything works as aexpected if I
turn on PROMISC on em0 but forwarding stops if I disable it, I can still
communicate with the router directly on the same logical network (for
example pinging interface adress on a vlan_if from a client on that vlan)
but all forwarding stops.

Some info:
net.inet.ip.forwarding: 1
net.inet.ip.fastforwarding: 0 (enableing this does not help)
net.inet.tcp.recvspace=1048576
net.inet.tcp.sendspace=1048576
kern.ipc.maxsockbuf=16777216

I use PF for filtering and disableing this does not help either.

Anyone with a clue?

//JO