I have a Golden Triangle setup using 2008 AD server and OS X 10.5.8 servers. All clients are 10.5.8. All clients have been imaged the same. On the clients IPv6 is turned off in the network system preferences but recently a few (7-8 out of 400) have changed IPv6 to "Automatically" under "Configure IPv6" in the advanced tab of the preferences. I have had the same setup on all clients for 2 years without this issue coming up. Does anyone know what could suddenly cause this change. When it happens, network users cannot log into the clients (shakes) and I have to turn off IPv6, then unbind from and re-bind to AD.