Thanks for the help John. I really appreciate it.
I tried to implement your suggestion but I can't. Whenever I configure static IP for IPv4 properties in Vista, the option (button) to set alternative IP disappears.
I did have that scenario before: dynamic as default then alternative IP. but same symptoms on undock-redock.
When I tried to put identical IP configurations in advanced options of IPv4 properties, Vista recognizes the redundant IP and doesn't allow me to continue.
Any other solutions I could try? Thanks

Originally Posted by
johngalt
Even though you do not connect to any other network, Vista recognizes that you have *disconnected* from the present network, and thus uses the settings in the alternate configuration to take over to try to keep a connection alive.
Unfortunately, for whatever reason, IPAPI is very tenacious and most times will not let go of the NIC once it takes over without (at the very least) a log out and log on, and usually forcing a reboot.
hence, my suggestion - change the alternate configuration settings to match those of your current settings - so that it will not attempt to change to an IPAPI assigned IP (169.254.xxx.xxx) and that should solve your problem.