Configure SSH Server

Disable root login
vim /etc/ssh/sshd_config

PermitRootLogin no

service sshd restart

Limit user login
vim /etc/ssh/sshd_config

AllowUsers user1 user2

service sshd restart

Change port
vim /etc/ssh/sshd_config

Port 10000

service sshd restart

Disable sftp
vim /etc/ssh/sshd_config

# Comment the following line
# Subsystem sftp /usr/lib/openssh/sftp-server

service sshd restart