We are running an ASA 5510 w/ 8.0(3) code that is isolating vendor systems from our network. We have an enterprise AD structure and the vendor has an internal AD structure for their system. Their systems exist on our network in a non-routed VLAN and the ASA has an interface inside that VLAN for traffic. If I disable the ASA interface, all connectivity within the VLAN functions normally (and I stress within the VLAN). If I enable the interface, the devices can no longer authenticate nor map network shares within the VLAN. A packet capture finds master browser elections that no one answers while the interface is enabled but the AD server answers when the interface is off. I have tried denying all traffic across the interface and even allowing all traffic. NETBIOS inspect, DNS inspect are turned on in the default inspect policy. Yes, the allow traffic between hosts on the same interface is enable as well. All the devices are physically connected to the same switch and exists in the same VLAN. Please forgive the lack of logs at this moment, I can't access them from home but will add in another post tomorrow. Any guidance or suggestions to look for is appreciated.