1. Web Authentication Layer is enabled with IWA realm
2. Management Console > Statistics > Authentication > Display by user
The domain\ComputerName$ is authenticated and cached in ProxySG.
3. After administrator manually logs out the domain\ComputerName$, the user can access the Internet
Management Console > Statistics > Authentication > Display by user
The domain\username or Anonymous users are authenticated and cached in ProxySG.
This is a known issue unique to ProxySG deployments where IP-based authentication surrogate modes are used with IWA.
For the possible root causes, refer to Intermittent Internet access problems when running Windows 7 or Windows Vista through the ProxySG
Common Solution is to implement Content Policy Language (CPL) to logout the ComputerName appended with $, and anonymous users.
<Proxy> condition=SILENT_USERS realm= user.login.log_out(true) define condition SILENT_USERS user="NT AUTHORITY\ANONYMOUS LOGON" user="Anonymous logon" user="NT AUTHORITY\Anonymous logon" user.regex=".+\$$" end