This block that shows last logins active and one link see all active logins. 
This block will only be visible for teachers (within the course) and managers 
(in and out of the courses).
The teacher can only see the active logins regarding the course, while the administrator 
can see all active logins on the platform.
Page all logins show the following information:photo, name, surname, Address IP, 
"Last access", "Session time" (as seen on the link "Participants" from the "People" block),
and a button to end the individual user session

Download the plug-in file from https://github.com/ed-rom/moodle-block_uniqueloginlist
Unzip the file to block plug-ins folder moodle/blocks/
Add block to a course