In file /etc/security/limits.conf the maxlogins field refer to what?
If I set
"user1 hard maxlogins 2"
Does this mean "user1" can have two concurrent login at a time or He can login only twice - still the system reboot again?
Possibly not, X sessions count as at least one login, as do terminal windows, and I believe shell scripts. In all likelihood, a hard limit of two there is way too few, I would suggest limiting the number of running processess vs the number of logins.