Create and manage users

# adduser username

# passwd username

Disable ssh access for the root user

# vim /etc/ssh/sshd_config

Go to the Authentication section.

# Authentication:
LoginGraceTime 120
PermitRootLogin yes
StrictModes yes

Replace the yes with no on the line PermitRootLogin and restart SSH service.

# /etc/init.d/ssh restart