iDRAC7 - Unexpected characters appear at Linux command prompt when closing remote console redirection screen

Remove the check mark in the box for "Automatic System Lock".   Apply the change.  Begin a new console redirect session and then close it.  The unexpected characters will be gone.

NOTE:  This option is present in FW versions 1.31 and 1.35 and above.

 
Additional Information:

When working at runlevel 3 (command line only) on a Linux machine through a console redirect session in an iDRAC7, you will find the following after closing the session and starting a new console redirect session.






These characters at the log in prompt appear after closing a console redirect screen and starting a new console redirect screen through the iDRAC.

Introduced in iDRAC7 firmware 1.30.30 is an option called "Automatic System Lock".  Log into an iDRAC7 and click the "Console" tab.  The bottom option on the page is "Automatic System Lock".  It is enabled by default.  

 

This option is present in FW 1.31 and in 1.35.

When running multiple TTY terminal sessions (ALT F1, ALT F2, ALT F3, etc) in a Linux environment, it has been seen that the last working TTY terminal session is closed.  If you are using TTY 6 and then close the iDRAC7 console redirect session, when starting a new session, TTY 6 is closed leaving TTY 5 being displayed.  TTY 5 displays the unexpected characters.

This is a security measure designed to lock a screen when closing a console redirect.  It is the equivalent of locking your workstation (Windows key L - or CTRL ALT DEL and lock).  The iDRAC7 sends a lock command.  This can only occur on a GUI.  There is no way to lock a command prompt only session.  This is why those unexpected characters show up.

The following info on the Automatic System Lock is pulled from the "help" section of the iDRAC7 itself:
 

Automatic System Lock