Is what each like to do most

If you chech Fail2ban logs, the ips change for similar ips, when they are banned.

Since I change the login attemps to one, at second try they are banned.

Looks like this persons change their IP by releasing their public IP to change to another public IP.

# vim /etc/ssh/sshd_config

Some changes to do to secure our server.

# /etc/ssh/sshd_config 
PermitRootLogin no
MaxAuthTries 1
PermitEmptyPasswords no

If you are a client, create your ssh-key in your local machine.

ssh-genkey 
# Give a name to identify that key: my-ssh-server

Copy that key to your server

ssh-copy-id -i ~/.ssh/server username@serverAddress
# insert password

Now connect to your server without using a password

ssh -i ~/.ssh/server 'username@serverAddress'

On your server side, change your ssh files permissions.

chmod 700 ~/.ssh 
chmod 600 ~/.ssh/known_hosts

Change sshd_config file:

# /etc/ssh/sshd_config
PubKeyAuthentication yes

No connections are possible without using ssh-keys.

Happy SSH sessions.

Crazy Life