Is there any way to detect whether Windows server is running in headed or headless?

Question

Is there any way to detect whether Windows 10 servers are running headed or headless mode using the command line? What thing get change when the user disconnects himself from the window server?

Answer 1

Query session should provide whether the user disconnected from RDP or logged out from the console, but with other remote access solutions there is no universal indication.

Here's an example of query session on a computer with an active console session (not headless):

C:\Users\foo>query session
 SESSIONNAME       USERNAME                 ID  STATE   TYPE        DEVICE
 services                                    0  Disc
>console           foo                       1  Active
 31c5ce94259d4...                        65536  Listen
 rdp-tcp                                 65538  Listen

and here's a counterexample of using psexec to get the output of query session from a machine with disconnected RDP users, and no one on the console session:

C:\Users\administrator>psexec \\target -s query session

PsExec v2.2 - Execute processes remotely
Copyright (C) 2001-2016 Mark Russinovich
Sysinternals - www.sysinternals.com


 SESSIONNAME       USERNAME                 ID  STATE   TYPE        DEVICE
>services                                    0  Disc
 console                                     1  Conn
                   jsmith                    3  Disc
                   Administrator            12  Disc
 rdp-tcp                                 65536  Listen
query exited on target with error code 1.

The definition of "headless" is also somewhat fraught, since VGA does not require backwards signaling, so if a server has no monitor connected, but is logged in and outputting video - is it "headless"? Does it know that it is headless?