On Fedora 3.3 kernel I see the same problem. tcpdumping the physical network interface eth0, I can see the DHCP replies coming through clearly, on VLAN 103, but tcpdumping eth0.103 (the trunked VLAN interface #103 associated to eth0), the DHCP replies simply do not appear. In both tcpdumps, the DHCP requests appear.
On Fedora 3.3 kernel I see the same problem. tcpdumping the physical network interface eth0, I can see the DHCP replies coming through clearly, on VLAN 103, but tcpdumping eth0.103 (the trunked VLAN interface #103 associated to eth0), the DHCP replies simply do not appear. In both tcpdumps, the DHCP requests appear.
So this is not fixed, and it goes beyond Ubuntu.