Just to add to the comments. I have had similar issues on my setup! It has driven me BatSh*t Crazy thinking it was something I had done wrong. it takes ages before I can get my Linux Server to fully register on an interface after the it has been unregistered for whatever reason. My current predicament is due to the DHCP Lease expiring. although it says the Interface is up and I can see the MAC is registered, things just are not getting through to the Server which is on a separate Subnet / VLAN2 Eth2 Interface from VLAN Eth0.
Its been driving me NUTS!!