What is the /admin switch in Microsoft Terminal Services Client (MSTSC) for Windows 2008 and Vista?

A. Although the /console switch no longer has any effect on Server 2008 and Vista Terminal Server connections, a new switch called the /admin switch has a similar effect when you use it to connect to a Server 2008 server with the Terminal Services role. When you use this switch with MSTSC, connections don't consume Terminal Services CALs.

The /admin switch involves elevated rights. If a user has the authority to use the /admin switch but has been marked with Deny Users Permissions To Log On To Terminal Server, he or she will be able to connect using mstsc /admin. Also, if a terminal server is in drain mode (no new sessions are accepted), an /admin session can still be created. The /admin sessions don't count toward the session limit that may be configured on a terminal server to limit the number of sessions.