Raja, If your machines are done doing 802.1x, and you aren't using the ISG for infranet auth, then UAC wouldn't be causing any issues. OAC does 802.1x at L2, but then everything else is windows. So from DHCP to all L3 activity, OAC isn't involved. Once 802.1x has completed, OAC tells windows that it has a "media connect". At that point windows goes out and does DHCP, and OAC will report back the IP address received through the OAC interface, but its done at that point. The only other thing I could think of would be switch timers. Maybe you are getting kicked off the network every now and then? I would think you'd be seeing a lot worse symptoms than outlook communications issues though. Are you looking to do source IP enforcement or VPN with UAC? You would want to configure your policies on your fw for infranet auth if you were going to do that. Also, for your vlan's, one reminder is that if you are using host checker with UAC, then your vlan's need to route back to the IC at least. The vlans don't need to go anywhere else, but they should allow traffic back to the IC's IP address so that the clients can talk to the IC at L3. Initital host checks can take place at L2, but periodic host checks or "monitor this policy for change" host checks require an active L3 connection back to the IC. If you continue to have problems, you could open a tac case and we can review the OAC logs to see if you are seeing disconnects. Otherwise I would try some debugging on the FW or running simple ping tests from your workstations. Thanks -Jeff
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