vim ~/.ssh/authorized_keys
cd /home sudo chmod 755 userName cd /home/userName sudo chmod 700 .ssh sudo chmod 600 .ssh/authorized_keys
Port 22 PermitRootLogin no PubkeyAuthentication yes AuthorizedKeysFile .ssh/authorized_keys
sudo systemctl restart sshd
ssh -i /home/userName/.ssh/keyName userName@hostname -p 22
PasswordAuthentication no
puttygen secretkey.txt -O private -o secretkey.ppk
sudo vim ~/.ssh/config
Host * HostKeyAlgorithms=+ssh-rsa PubkeyAcceptedAlgorithms=+ssh-rsa