1. Most of these are done by script kiddies. They get a script and
run it is tries to connect via standard port 22.
2 Defense in depth.
A. Non-standard port.
B. Only allow users that require login via ssh which should never be root.
C. Require key login no passwords.
D. use sudo and sudrestrictions to prevent loading a shell as root.
I changed the port to 6000, restart sshd /etc/init/sshd restart and login
via new port 6000 sucessfully. But it takes a longer time to process a
command.
eg. default port 22
ps aux takes 2 sec
on port 6000
ps aux takes 45 sec.
What happened?
regards