Do I understand it correctly that your startup script contains code that is
changin IP address of the system when it runs? Startup script processing is
synchronous by default and unless you change this, must finish before user
logon or time out.
Also, in properly designed system reauthentication mustn't change VLAN or
IP. Is that feature someting unique to your environment? I have seen bad
cases of overengineering resulting in effects like this.
Svyatoslav Pidgorny, MS MVP - Security, MCSE
-= F1 is the key =-