Limit concurrent logins

Login limits are set in /etc/security/limits.conf
Edit file with folowing syntax:
	<user or @group>		<limit type soft|hard>	<what to limit>		<value>

Limit profe account logins:
	profe		hard		maxlogins		2

Limit student account logins:
	@students	hard		maxlogins		5



Test by beginning multiple ssh sessions until limit is reached and error is given.